# FAQ: Radiator, Cooling Fan, and A/C



## groggory (Apr 21, 2003)

I enjoy making FAQ's...so I think I'll write one up on the cooling issues that seem to frequent the forum so often.

I'll also include performance upgrades.

This is going to be geared towards cars that came stock with 1.8t's. If you have a car that has a 1.8t swapped into it...well...you're on your own.

*Symptoms*


A/C won't get cold
Main Cooling Fan won't turn on
A/C cooling fan won't turn on
Main Cooling Fan won't turn on high
A/C cooling fan won't turn on high
Main cooling fan won't turn on 'low'
A/C cooling fan won't turn on low


----------



## groggory (Apr 21, 2003)

> In case the link disappears in the future: "On this vehicle, the cooling fan and A/C compressor operation are controlled by the J293 fan control module, which is usually located in the driver's front corner of the engine compartment on the lower frame rail. The J293 module has both a 14-pin connector identified as the T14 connector in Volkswagen wiring diagrams and a four-pin connector identified as the T4a connector. To diagnose this system, starting on the T14 connector:
> 1) Start and idle the vehicle. Select "A/C on" at maximum cooling and "blower on" at high speed.
> 2) Check for 12 volts at the T14 connector pin No. 8 (T14/8). This 12-volt signal comes from the A/C switch and requires both cooling fans on at low speed and compressor activation.
> 3) Check for 12 volts at pin T14/9. This voltage is a switched ignition source and will have 12 volts when the ignition is in the "on" position.
> ...





Andaloons said:


> 1. To test a fan motor, unplug the electrical connector at the motor and use fused jumper wires to connect battery power and ground directly to the fan. If the fan does not operate, replace the motor.
> 2. If the motor tests OK, check the cooling fan thermo switch, located at the bottom of the radiator on the driver's side.
> 3. Remove the electrical connector from the cooling fan thermo switch and apply a fused jumper wire between terminals number 1 and number 2 with the ignition switch in the ON position, with the engine not running. Both engine cooling fans should run at low speed.
> 4. Next apply the fused jumper wire between terminal number 2 and number 3 with the ignition switch ON and the engine not running. Both engine cooling fans should run at high speed.
> ...





radlynx said:


> "On this vehicle, the cooling fan and A/C compressor operation are controlled by the J293 fan control module, which is usually located in the driver's front corner of the engine compartment on the lower frame rail. The J293 module has both a 14-pin connector identified as the T14 connector in Volkswagen wiring diagrams and a four-pin connector identified as the T4a connector. To diagnose this system, starting on the T14 connector:
> 
> 1) Start and idle the vehicle. Select "A/C on" at maximum cooling and "blower on" at high speed.
> 
> ...


A/C smaller fan part# 1C0959455C (female connector)
Engine bigger fan part# 1J0959455S (male connector)


----------



## groggory (Apr 21, 2003)

> in my experience the low speed on the big fan burns out first..you ac will still work just not as well especially sitting in traffic, i would replace it asap
> 
> you need to check the coil on the ac clutch.
> 
> ...





easthk said:


> Here is my DIY on replacing the primary (large) fan and the Fan Control Module.
> 
> I had the problem where my AC wouldn't work and my large fan wouldn't engage. (It was toast - when you turned it by hand the grinding told you it was dead).
> 
> ...


thanks for the tips


----------



## groggory (Apr 21, 2003)

2000 VW Jetta 1.8T AWD / MK4

Radiator/Condensor Dual Fan Assembly w/Shroud Complete
VW Part# 1J0-121-207-AA / 1J0121207AA
Partslink# VW3115103

**Also Compatible #1JO-959-455-C / 1J0959455C


----------



## groggory (Apr 21, 2003)

I'll share my coolant flush method...

1) Drain radiator.

2) Remove thermostat housing and remove thermostat. Coolant will start making a mess, so be quick. Replace housing.

3) Remove your upper radiator hose from your radiator. Remove your lower radiator hose from your radiator. If desired, run hose water through the radiator and drain that out too. 

4) Put a garden hose into your upper radiator hose and turn the water on. Old coolant will come pouring out of the lower radiator hose. Catch this into a bucket. Keep running water into your engine until it is clear. When it's clear stop the garden hose and replace the lower coolant hose onto the radiator.

5) Undo the thermostat housing and replace the thermostat. This is a good time to put a new thermostat in while you're at it. If you are putting a new one in make sure you do the old drill trick. Drill a ~1/16" hole in the side of the thermostat so any air bubbles can make their way past it. Screw the thermostat housing back down. Try to do this quick so you lose the least amount of water as possible while doing this.

7) Fill the coolant ball up with G12. It will slowly start feeding into the radiator. Just be slow and take your time until it won't take anymore.

8) Replace the upper radiator hose.

9) Start the engine. Keep an eye on the coolant ball and as the engine starts bubbling up air bubbles into the coolant ball keep topping it off with G12. Do not overfill the coolant ball..fill up to the MAX line. This is important. Keep doing this until the car has gone through a few radiator cycles.

10) Cap the radiator ball and go for a ~20 minute drive. Park on a level surface and fill the coolant ball up to the max mark with G12.

This process of pure water in the block and concentrated G12 in the radiator equates to roughly a 50/50 mix of G12 and water. Also, driving around for awhile will cause the two liquids to mix naturally.

Note: If you live in an area with particularly hard water such as an area that gets its water from well water then do not use hose water for the flushing portions of these directions. Instead go to the grocery store and use a long funnel and distilled water. The G12 mixture will prevent mildly hard water from calcifying in your engine...but it won't save you from super hard water.

Not that hard...will probably take you about an hour.


----------



## Andaloons (Apr 16, 2004)

groggory said:


> I enjoy making FAQ's...so I think I'll write one up on the cooling issues that seem to frequent the forum so often.


It's lucky you're good at making the FAQ's and summer is right around the corner for this one! :thumbup:


----------



## radlynx (Jan 4, 2007)

i felt horrible for you. nobody is interested to your problem. fortunately, i have the same problem, only the slow speed on both fans don't work. high speed works. so this time, i'm interested to share what i learned.

here's what I did, i unplugged the connector at the bottom of the radiator for the fan switch (driver side of the radiator). it's a 3 wire connection. you need to do this to check if your fan is defective or not. 
1. unplug the connector, there should be 3 wires. lets say wires A, B, C.
2. switch the key to on position
3. get a tester and check which wire is live. (there should only be one live wire) lets say that is wire A.
4. short wire A to wire B, both fan should come on slow or fast. if not, it's defective.
5. short wire A to wire C, both fan should come on slow or fast. if not, its defective.

whichever fan that don't turn on, that is defective. you will need to replace the fan itself. i hope this helps. if the fan turns on while you are testing it, it could be that your fan switch (3pins) or the fan control module is defective. i hope this helps.






groggory said:


> I enjoy making FAQ's...so I think I'll write one up on the cooling issues that seem to frequent the forum so often.
> 
> I'll also include performance upgrades.
> 
> ...


----------



## gbisus13 (Aug 16, 2005)

does anyone know what the voltages to the rad fans are at the different settings? I'm swapping to aftermarkets and need to know if it turns 1 on at 12V and then the second at 12V (rad temperature controller, 2 step thermoswitch. I deleted AC so that won't kick on the fans either condition), or does one of the temp control settings send 24V to one (or both) of the fans? It hasn't been warm enough/enough running time to get the rad to temp to put a voltmeter on it.


----------



## radlynx (Jan 4, 2007)

it only uses 12 volts on low speed and high speed.




gbisus13 said:


> does anyone know what the voltages to the rad fans are at the different settings? I'm swapping to aftermarkets and need to know if it turns 1 on at 12V and then the second at 12V (rad temperature controller, 2 step thermoswitch. I deleted AC so that won't kick on the fans either condition), or does one of the temp control settings send 24V to one (or both) of the fans? It hasn't been warm enough/enough running time to get the rad to temp to put a voltmeter on it.


----------



## Sketchykid (Aug 3, 2005)

id love to see a writeup on bypassing the fan switch so you can operate the fans (and afterrun coolant pump) on a on off switch from inside the car.


----------



## groggory (Apr 21, 2003)

Sketchykid said:


> id love to see a writeup on bypassing the fan switch so you can operate the fans (and afterrun coolant pump) on a on off switch from inside the car.


Super easy.. Apply 12V to the fans on either the high or low circuit. Appropriate relays, etc.

If this is a common request I'll do it.


----------



## radlynx (Jan 4, 2007)

It's better to have the fan switch than bypassing it. it works well. if it's a manual switch, you might end up forgetting it and ran out of battery. the reason sometimes it does not work is because the fan itself is no longer working or have a bad resistor. easy way to test it is to switch on the a/c. fan should run in slow speed mode. super easy to check the fan if it's defective.




Sketchykid said:


> id love to see a writeup on bypassing the fan switch so you can operate the fans (and afterrun coolant pump) on a on off switch from inside the car.


----------



## radlynx (Jan 4, 2007)

Groggory, did you fix your fan problem?



groggory said:


> Super easy.. Apply 12V to the fans on either the high or low circuit. Appropriate relays, etc.
> 
> If this is a common request I'll do it.


----------



## groggory (Apr 21, 2003)

radlynx said:


> Groggory, did you fix your fan problem?


I don't have a fan problem. I was going to make a general purpose FAQ for all these sorts of problems.


----------



## hootyburra (Feb 19, 2007)

:beer: for you


----------



## Lythandra (Nov 19, 2006)

Be sure to show how you unplug the fan switch connector.

Whats the trick because I cannot get mine off .....


----------



## groggory (Apr 21, 2003)

Lythandra said:


> Be sure to show how you unplug the fan switch connector.
> 
> Whats the trick because I cannot get mine off .....


The fan switch on the radiator? The one that's trangular shaped?

* Push the connector tightly in...then push the connector click lock open a bit with a flathead screwdriver, then while holding that open, pull the connector...

same as every other connector on our VW.

lol, don't take my advice though. 3 out of 4 of my coilpack connectors are broken due to my impatience


----------



## Sketchykid (Aug 3, 2005)

ill have to take a closer look, i am chasing other gremlins right now....

thanks for the write up./


----------



## bunnyspeed (Jul 8, 2003)

quick question. 
should aux fan spin freely as the large fan does?


----------



## groggory (Apr 21, 2003)

bunnyspeed said:


> quick question.
> should aux fan spin freely as the large fan does?


Yes, you should be able to easily turn it


----------



## bunnyspeed (Jul 8, 2003)

Thank you! That's what I was assuming. I'll add that to my growing repair list.


----------



## hgrail (Nov 21, 2002)

Here is my DIY on replacing the primary (large) fan and the Fan Control Module.

I had the problem where my AC wouldn't work and my large fan wouldn't engage. (It was toast - when you turned it by hand the grinding told you it was dead).

I replaced the fan and fan control module in about a half hour. Including prep and cleanup and testing this whole thing took me about an hour total. One of the easier things I've done on this car to tell you the truth.

1 run car up on ramps
2 remove belly pan and both engine covers
3 remove cable covers (behind right headlamp), battery box cover and disco recirc tube that goes to the intake box (tuck it out of the way as best as you can)
4 get under car & disco cable for large fan and undo lower torx nut holding fan housing in place
5 remove top 2 torx nuts holding fan in place - and boogie that assembly around the rad hoses & assorted other plumbing to get it out the top. Take your time - don't brake anything. Those stupid hard plastic hoses are expensive.
6 unmount old fan from support & mount new fan. Boogie new fan down behind radiator - again take your time. Replace all 3 torx bolts
7 get under car & plug fan in
8 start car up - turn on AC (fan should engage) - let car warm up to full temp at idle (fan should engage then also).

If no go - then FCM is likely toast also (like mine was)

1 disco neg terminal of battery (if you have't already because you are lazy like me)
2 with light look down in front of battery pan - if you know what you are looking for you will recognize the top of the FCM held in place by one or two bolts. Get your wrench with a foot long extension and remove bolt - don't drop and lose it!
3 climb under car - pull down old FCM and unplug connectors. 
4 grab new FCM - and hold in place from top of car and get bolt started using extension and tighten it down. 
5 get under car - Hit connectors with dialectic grease (always a good idea for wet environments) and plug 'em in good & tight
6 retest as above. If you are lucky your fan is working in both scenerios! Go have a beer
7 Come back at some point - put all covers back in place and clean up after yourself.

This worked well on my 2001 Jetta 1.8T Wolfsburg. I can't believe the garage was going to charge me $1,100 for this.. :screwy:


----------



## easthk (Oct 10, 2004)

hgrail said:


> Here is my DIY on replacing the primary (large) fan and the Fan Control Module.
> 
> I had the problem where my AC wouldn't work and my large fan wouldn't engage. (It was toast - when you turned it by hand the grinding told you it was dead).
> 
> ...



hgrail's instructions worked good for changing out the main fan- a couple extra tips on above steps:

4. Access to fan connector: pull down the driver's side vertical plastic splash guard for better access, plus its a little easier to reach if you loosen up the fan and slide it out of the way. To disconnect, either pull backside of connector towards fender or slide clip assembly up out of the slot, then pull apart.
5. after removing the fan's 3 torx screws I was unable to completely boogie the assembly out past all hoses, so the fan support (3 nuts) was removed; fan support piece was left in place and then slid the dead fan down past all the hoses (still a tight squeeze past the lower radiator hose).
6. Slide new fan up into place and reposition fan support over center- thread wires through center of fan support hole but be careful to align wires corrrecty and not pinch them between fan support. Once aligned, tighten 3 fan support nuts. Tighten 3 torx screws (I replaced corroded torx with 3 new stainless sheet metal screws). Clip all hoses and wires back into supports.

Plug in, test, go grab a beer


----------



## groggory (Apr 21, 2003)

Thanks. I updated the FAQ. This is my least refined FAQ. I need to go back and fill in lots of details when I get a chance.


----------



## matty675 (Oct 2, 2011)

when testing the fcm, how do you know which pin is which?

is it okay to have the fcm unplugged while the engine is running? what is the best way to do this? it seems like it would be hard to get to without unplugging it...


----------



## Big_Tom (Aug 19, 2007)

Nice work G :thumbup:


----------



## Charlie_M (Mar 23, 2011)

matty675 said:


> when testing the fcm, how do you know which pin is which?
> 
> is it okay to have the fcm unplugged while the engine is running? what is the best way to do this? it seems like it would be hard to get to without unplugging it...


IIRC, the pinout is printed on the side of the switch. Check pictures at ecstuning. If you have the bentley, you can go by the wire color codes too.

To check the pin voltages on a system that's still hooked up, use a sharpened needle-point tip for your voltmeter, and just go right through the wire insulation. If you are worried about the small hole you leave behind, dab it with silicone, but I usually don't bother.


----------



## matty675 (Oct 2, 2011)

its under the battery tray though... should i remove the battery tray, unbolt the fcm while keeping the harnesses connected and then do it?


----------



## Charlie_M (Mar 23, 2011)

matty675 said:


> its under the battery tray though... should i remove the battery tray, unbolt the fcm while keeping the harnesses connected and then do it?


Don't remove the FCM unless it tests bad ... you unbolt it from the top, but you get at all the connectors from the bottom, so test it first. You need the battery hooked up to do the tests ...


----------



## .:RyouExperienced (Sep 19, 2005)

rad lynx said:


> whichever fan that don't turn on, that is defective. you will need to replace the fan itself. i hope this helps. if the fan turns on while you are testing it, it could be that your fan switch (3pins) or the fan control module is defective. i hope this helps.


So I have a 12v at the red wire on the therm switch and it powers up both fans on the low speed when jumpered but not the high speed on _both of them_. I just want to make sure that this means that _both_ my fans need to be replaced. I just find it odd that both fans would loose their high speed settings at the same time. Can anyone confirm this please?


----------



## groggory (Apr 21, 2003)

.:RyouExperienced said:


> So I have a 12v at the red wire on the therm switch and it powers up both fans on the low speed when jumpered but not the high speed on _both of them_. I just want to make sure that this means that _both_ my fans need to be replaced. I just find it odd that both fans would loose their high speed settings at the same time. Can anyone confirm this please?


Each fan has a 3 pin connector.

one pin is high speed, one pin is low speed, one pin is ground.

Test your fans individually like that.

...

To test your FCM

take a piece of wire and jumper the three pin connector that plugs into the temp switch in radiator

one pin to middle is high speed
one pin to middle is low speed

This tests your FCM

...

If both your fans AND your FCM test out, then it's your coolant temp switch in the radiator.


----------



## .:RyouExperienced (Sep 19, 2005)

groggory said:


> To test your FCM
> 
> take a piece of wire and jumper the three pin connector that plugs into the temp switch in radiator
> 
> ...


Since both fans work at both speeds but then only work at the low speed through the therm switch in the radiator would it be safe to assume the FCM is done?


----------



## l88m22vette (Mar 2, 2006)

Any info on mk4 VW/mk1 TT radiator upgrades? I've heard the stock one is good, I've heard the Mishimoto is "better" but fitment sucks, and I know someone makes an upgraded (3-core?) radiator as well. Info on upgrades would be awesome (products, links, etc) :thumbup:


----------



## groggory (Apr 21, 2003)

.:RyouExperienced said:


> Since both fans work at both speeds but then only work at the low speed through the therm switch in the radiator would it be safe to assume the FCM is done?


There can also be a problem with the climate control
Panel in the cabin


----------



## .:RyouExperienced (Sep 19, 2005)

groggory said:


> There can also be a problem with the climate control
> Panel in the cabin


Could you tell me more about this? I know that the a/c kicks on the aux fan through the FCM but if I understand correctly, it doesn't affect the large rad fan operation.

I've searched and found no mention of this in bentley.


----------



## groggory (Apr 21, 2003)

.:RyouExperienced said:


> Could you tell me more about this? I know that the a/c kicks on the aux fan through the FCM but if I understand correctly, it doesn't affect the large rad fan operation.
> 
> I've searched and found no mention of this in bentley.


I'm not 100% on how this works. My brother was having a problem similar to yours. I took it to my shop. They figured out there was a problem with the cabin HVAC controls. Replaced them. Everything started working.

Sorry.


----------



## .:RyouExperienced (Sep 19, 2005)

That's okay. I have no reason to believe the HVAC controls aren't working and every reason to believe the FCM is dead, especially considering the car had a front end collision months back.

Thanks for all the help greg. Many :beer::beer::beer: to you!


----------



## sublimnl (Feb 18, 2001)

Is it necessary to remove the front bumper if I am going to replace both fans? I ordered a whole new setup (fans, shroud, wiring, etc) and I'm hoping I can just get the car up on a lift and be able to get access to everything necessary and slip out the old parts without taking off the bumper. Thanks guys.


----------



## groggory (Apr 21, 2003)

sublimnl said:


> Is it necessary to remove the front bumper if I am going to replace both fans? I ordered a whole new setup (fans, shroud, wiring, etc) and I'm hoping I can just get the car up on a lift and be able to get access to everything necessary and slip out the old parts without taking off the bumper. Thanks guys.


Bumper stays on


----------



## TurboTastic (May 20, 2010)

*Help with Fans Please.*

Ok so yesterday my AC (which has not really been blowing cold air even after charging with freon) started to get warm and then my high temp alert chimed and I heard a strange noise. I shut the car off and waited for it to cool down. I put the key in the ignition to on position and turned on the AC, went to check fans, big one on drivers side not working, small one on passenger side making a strange noise and not turning. So in essence, both fans not working. I reached in and moved the large blade manually without any problem. When I did the same to the small one, I discovered it was completely loose and not turning because it was off either the motor or shroud, cant tell because I don't really know what I am looking for but I do know its making noise when I turn on the AC but not spinning and not attached to anything, its kinda just hanging there, although i cant just pull it off, so it is attached to something. Any advice or help would be appreciated. Where do I start and can anyone tell me the best way to get the shroud off so I can see what happened with the loose fan or at least an easy way to get to it. Thanks! :banghead:


----------



## radlynx (Jan 4, 2007)

try to read this thread from the start. it will give you answers on how to test the fan. from what you described, you need to replace both your fans.



TurboTastic said:


> Ok so yesterday my AC (which has not really been blowing cold air even after charging with freon) started to get warm and then my high temp alert chimed and I heard a strange noise. I shut the car off and waited for it to cool down. I put the key in the ignition to on position and turned on the AC, went to check fans, big one on drivers side not working, small one on passenger side making a strange noise and not turning. So in essence, both fans not working. I reached in and moved the large blade manually without any problem. When I did the same to the small one, I discovered it was completely loose and not turning because it was off either the motor or shroud, cant tell because I don't really know what I am looking for but I do know its making noise when I turn on the AC but not spinning and not attached to anything, its kinda just hanging there, although i cant just pull it off, so it is attached to something. Any advice or help would be appreciated. Where do I start and can anyone tell me the best way to get the shroud off so I can see what happened with the loose fan or at least an easy way to get to it. Thanks! :banghead:


----------



## TurboTastic (May 20, 2010)

radlynx said:


> try to read this thread from the start. it will give you answers on how to test the fan. from what you described, you need to replace both your fans.[/QUOTE
> 
> Fan tested and dead. Trust me I read the thread over and over  Still looking for a good DYI on removing the fans and or entire shroud at this point. Any ideas or links would be much appreciated. Seems like it shouldn't be too much of a big deal but any information is always helpful.


----------



## Ktt88 (Aug 27, 2011)

I've been having problems with my AC, well by problems I mean that it doesnt work at all

Nothing happens when I press the AC switch inside the car (light does come on)

Fans do no turn on as well

I attempted to do some troubleshooting on the first page of this FAQ to see if my fan motors were good or bad

_1.To test a fan motor, unplug the electrical connector at the motor and use fused jumper wires to connect battery power and ground directly to the fan. If the fan does not operate, replace the motor._

Does this mean simply connecting 2 wires from the battery to the fan plug?


----------



## groggory (Apr 21, 2003)

Ktt88 said:


> I've been having problems with my AC, well by problems I mean that it doesnt work at all
> 
> Nothing happens when I press the AC switch inside the car (light does come on)
> 
> ...


Battery (+) -> Fuse -> fan plug
Battery (-) -> fan plug


----------



## Ktt88 (Aug 27, 2011)

groggory said:


> Battery (+) -> Fuse -> fan plug
> Battery (-) -> fan plug


sorry...not sure what you mean when you say

Battery (+) -> Fuse -> fan plug


----------



## groggory (Apr 21, 2003)

Ktt88 said:


> sorry...not sure what you mean when you say
> 
> Battery (+) -> Fuse -> fan plug


Attach a wire to the battery positive pole on your battery.

Attach that wire to one side of a fuse.

Attach another wire to the other side of the fuse.

Attach the end of that wire to one side of the fan plug.


----------



## radlynx (Jan 4, 2007)

thanks for the info. when i replaced my fan a year ago, i had to remove the front bumper and removed the radiator support. when you do remove the radiator support, please make sure to support the bottom of the radiator so it's not hanging by itself. once you have more clearance between the engine and radiator, you should be able to remove the fan shroud easily. also, you need to remove the electric waterpump attached to the shroud. you don't need to remove any coolant or drain it at all. space there is not enought if you don't do all these. i hope this helps.

this will help you do it more quicker and reinstall it much faster. 



TurboTastic said:


> radlynx said:
> 
> 
> > try to read this thread from the start. it will give you answers on how to test the fan. from what you described, you need to replace both your fans.[/QUOTE
> ...


----------



## Chunki84 (Dec 18, 2008)

that's what I done so far, 
1. both fan motors are working slow or high. 
2. I changed coolant temperature sensor. 
3. I changed a/c switch located on high port of ac pipe. 
4. I changed fan control unit three times. 
5. I checked all fuses. 
6. I checked voltages that go to fan switch on radiator. both voltage around 11v. 
7. I checked temperatures from climate control unit, all temperatures can be read find. 
8. No voltage found connector that attached to compressor clutch even I set lowest desired 
temperature. 
9. If I wire compressor clutch with battery directly, cold air blow in to car. 

What's wrong;;;


----------



## RabVr6 (Nov 28, 2011)

Wow, my issues are almost identicle to yours. I changed the FCM and my radiator fans still don't work when ignition is on "on" position, engine off. Tested my fans, both speeds work. If I jump my compressor, coil engages. No voltage at compressor connector. Now my climate control unit in cabin blinks multiple times before settling. I am now totally out of suggestions. Could the aftermarket FCM. Be shot? Does anyone know how to test the 10 pin. All I see are troubleshooter for the 14 pin. Any other relays that might be shot?? Please help. Sweating balls in nj lol


----------



## pattrick (Apr 15, 2011)

RabVr6 said:


> Wow, my issues are almost identicle to yours. I changed the FCM and my radiator fans still don't work when ignition is on "on" position, engine off. Tested my fans, both speeds work. If I jump my compressor, coil engages. No voltage at compressor connector. Now my climate control unit in cabin blinks multiple times before settling. I am now totally out of suggestions. Could the aftermarket FCM. Be shot? Does anyone know how to test the 10 pin. All I see are troubleshooter for the 14 pin. Any other relays that might be shot?? Please help. Sweating balls in nj lol


 


To diagnose this system, starting on the T10 connector: 
1) Start and idle the vehicle. Select "A/C on" at maximum cooling and "blower on" at high speed (high speed just keeps the compressor loaded, signal development is the same for any speed). 
1a) First check for 12 volts at pin 1 of N25, the AC clutch connector, if voltage is not present go to step 2. 
1b) if 12 volts is present on Pin 1 of N25, then check for continuity to ground at pin 2 of the AC clutch connector. 
1c) If these are both good, check for continuity through the clutch coil. It must be bad. 
2) Check for 12 volts at the T10a connector pin No. 8 and 5 (T10b/8, T10b/5). This 12-volt signal comes from the A/C switch and requests both cooling fans on at low speed and compressor activation by the Fan Control Module. (Through fuse 25, the fresh air blower switch, the AC switch, F129 pressure switch , F38 ambient temperature switch, and F163 A/C high temperature cutout switch. This signal is also sent to the ECM, Engine Control Module.) If this voltage is not present, drop down to section B. 
3) If you had voltage on T10b/8, and T10b/5, Check for 12 volts at pin T10b/9. This voltage is a switched ignition source and will have 12 volts when the ignition is in the "on" position.(Through fuse 5.) 
4) Check for 12 volts at pin T10b/4. This is a constant battery source and should read 12 volts at all times from fuse S16. 
5) Check for a good ground at pin T10b/6. 
6) Check for 12 volts at all times at the four-pin connector, T4a pins T4a/4 and T4a/3 from fuses S164 and S180, respectively. 
7) Check for an 11-volt reference voltage at pin T10/3. The reference voltage originates in the J293 fan control module and can be grounded by the control module (ECM) under certain circumstances (typically wide open throttle or vehicle overheat conditions) to turn the A/C compressor off. 
7a)If zero volts are present, the PCM is commanding "compressor off" or the wiring harness is shorted to ground. Raise vehicle idle speed above 2500 rpm and observe compressor operation and voltage at pin T10b/3. If the voltage at pin T10b/3 returns to 11 volts with the idle speed above 2500 rpm and compressor operation resumes, then a throttle basic setting procedure is needed and must be performed with a factory-compatible, by-directional scan tool. Note: A loss of throttle basic settings will keep the compressor from activating. (I just left this section in from the 2000 and on version…I have no idea if this is the case for the early version of the vehicle or not, DanG144.) 
8) If all previous tests have passed, check the T10b connector pin T10b/10 for 12 volts. This pin is the output signal to the compressor clutch coil. If all the other tests have passed and there is no voltage at pin T10b/10, this indicates a faulty fan control module. As you can see, turning on an A/C clutch is not a simple function on late model vehicles, and systems that you might not associate with an A/C problem can stop you and your customer from keeping cool. Be sure to check Direct-Hit's Hotline Archive section for more diagnostic procedures and tips. 
Section B (from section A step 2) 
If 12 volts is not present on T10b/8 and T10B/5 you need to find out why - and there can be many reasons. 
1) Verify Fuse 25 is good, with voltage on both sides. Make sure. 
2) Check the halfway point. Verify 12 volts are present on Pin 2 (blue and red wire) of the F129 connector (pressure switch located in A/C line near firewall and expansion valve. If not go to step 8, the problem is in the first half of the circuit. 
3) So you had 12 volts on F129 pin 2, verify continuity from pins 1 to 2 on F129, and reinstall the connector. You should definitely have continuity if the A/C pressures are between 1.2 and 24 bar (17.4 and 348 psig). [The high pressure switch opens at 32 bar (464psig) and closes back at 24 bar (348 psig), so it is sometimes closed between these pressures and sometimes open] If continuity is good, reinstall the connector. If bad, check the pressures. If pressures are good and continuity is bad, you have a bad pressure switch. 
4) If everything checks out so far, check 12 volts present at pin 2 of F38, the Ambient Temperature Switch. If not, your wiring must be bad from F129 to F38. If 12 volts is present at pin 2, check the continuity of F38. This switch should have 0 ohms if temperature is above 45 degrees F. (it opens at 30F, closes at 45 F). Reinstall the connector. 
5) If everything checks out so far, check 12 volts at pin 1 of F163, the A/C thermal cutout switch. If 12 volts is not present, the wiring must be bad between F38 and F163. If 12 volts is present, check the continuity of F163. F163 should be closed (0 ohms, have continuity) unless the A/C temperature is greater than 234 F (opens at 246F, closes at 234 F.) 
6) If everything is good so far, follow the green wire off of pin 2 of F163 until you find a junction - L10 – named “wire connection-2- in A/C wiring harness” the green wire is headed for pins T10b/8 and T10b/5. No further clues as to location. At this junction wires will connect from the three terminals mentioned (and PM Dang144 with the location, pictures would be good). Theoretically the car is still running with the A/C on and a fan speed selected, so be careful to not short these wires to ground. (More likely, after you locate this connection, turn the car and A/C back on to check the voltage. Have the car off if you disassemble and clean this connection.) 
7) There is nothing left but wire to pins T10b/8 and T10b/5. IF the problem was in the second half of the circuit, you should have found it. 

8) If the voltage in step B2 was bad at pin 2 of F129 the problem must be in the first half of the circuit. Check for 12 volts at pin T8b/1, the 8 pin connector on the A/C switch. If 12 volts is present then the problem must be in the wiring between these two components, which includes L9 “wire connection-1-in A/C wiring harness (pm DanG144 with location and pics) and T10/2 “10 pin connector, orange, in protective housing for connectors in plenum, left” pin 2. Reinstall connectors. 
9) If voltage is not present at T8b/1, check for voltage at T6d/2 pin 2 of the 6pin connector on the fresh air blower switch. If voltage is present then the fresh air blower switch is bad or L45 “wire connection, in A/C harness” or the wires themselves between these two components are bad. Reinstall the connectors. 
10) If voltage was not present on T6d/2 then check that voltage is present on T10j/1 “10 pin connector behind instrument panel, center.” You are down to just this connector and wiring between Fuse 25 and T6d/2. You did start out by verifying that Fuse 25 had voltage on both sides, right? Right? 
This simple circuit test took me forever to write, and is best understood with the Bentley section 14 of the wiring diagrams, pages 97-152 to 97-156. 


Hope it helps!


----------



## RabVr6 (Nov 28, 2011)

Patrick, you are a godsend. I will try this procedure in the AM! Thank you mate !!


----------



## jason bouchard (Aug 25, 2005)

01 audi tt 225Q 110k miles 

So my a/c and after run water pump both quit. 

the fans come on both when I turn on the A/C and when the car gets too hot. 

The ac is blowing hot air and the clutch wont kick in. 
I checked the a/c r134 and its got the right amount of pressure. 

I checked the fuses from the top of battery fuse box, and I touched a screw driver one both sides of each of the fuse posts to see if the fuses were blown, but nothing made the a/c clutch kick on. Also, oddly the first wire on the fuse box on top of the battery (the black one listed as generator in the pic above) Gets VERY hot and burns to the touch when the car is on. . . i don't know what thats about. 


any ideas ? the a/c was making a high pitched whine noise when I first turn on the car with it on for a while now, but would go away if I drive the car or if I turn the A/C off. 


where is the a/c clutch unit plug located at that I can run a Hot line straight to to test if the A/C will kick on. 

Thx 

:thumbup:


----------



## TTcruZin69 (Nov 26, 2009)

Did the dig. on the connector worked flawlessly and found out my large fan wasn't working. Now both do with slow and fast speed. Now my prob. is they wouldn't turn on while the #16 fuse is in when the car is on or on the on key position y is that? please help. checked fuse on top of battery wit test light and its doing it's job.


----------



## .:RyouExperienced (Sep 19, 2005)

Any update on whether your FCM checked out RabVr6? 

My scenario: 

ALL fuses are good 
Both fan speeds work 
Thermoswitch checks out with 12V from red wire 
Replaced FCM with "New" OEM eBay one and still nothing... 

 Any one with any idea on what else I can check? Wiring all looks good too.


----------



## TTcruZin69 (Nov 26, 2009)

solved my problem wasn't one hahaha thanks for help nott!!:thumbdown:


----------



## groggory (Apr 21, 2003)

Excellent thread regarding the A/C Cutout Switch (duty cycle switch)

http://forums.vwvortex.com/showthre...-engine-have-the-AC-Cutout-temperature-switch


----------



## .:RyouExperienced (Sep 19, 2005)

Question!

Bentley states that when the car warms up (and begins to overheat) the thermoswitch should open allowing coolant to flow through the radiator and the lower radiator hose should feel hot.

If the lower hose remains cold while the engine begins to overheat would it be safe to assume the thermoswitch is bad?


----------



## groggory (Apr 21, 2003)

.:RyouExperienced said:


> Question!
> 
> Bentley states that when the car warms up (and begins to overheat) the thermoswitch should open allowing coolant to flow through the radiator and the lower radiator hose should feel hot.
> 
> If the lower hose remains cold while the engine begins to overheat would it be safe to assume the thermoswitch is bad?


The water pump could also be bad. The water pump is what makes the water circulate.

There could also be an air bubble in the system that is preventing the coolant from circulating


----------



## .:RyouExperienced (Sep 19, 2005)

groggory said:


> The water pump could also be bad. The water pump is what makes the water circulate.
> 
> There could also be an air bubble in the system that is preventing the coolant from circulating


I just replaced the water pump maybe 20,000 miles ago so I feel like that would be unlikely. How would you purge the potential air bubble from the system? Would a simple drain, flush, refill do the trick?


----------



## groggory (Apr 21, 2003)

.:RyouExperienced said:


> I just replaced the water pump maybe 20,000 miles ago so I feel like that would be unlikely. How would you purge the potential air bubble from the system? Would a simple drain, flush, refill do the trick?


Try this...

park your car on a slanted driveway with the nose pointed in the air.

Remove the coolant ball cap

Idle the engine for awhile and watch the coolant ball. See if bubbles come bubbling out.

...

There's another way, but I don't like to recommend it to people because it's kinda tricky and only marginally safe...

1) Get the car hot
2) Put on some thick gloves and long sleeves and safety glasses
3) Make sure your coolant ball is full to the mark
4) Use pliers and slide the upper coolant hose clamp back on the hose
5) Pull the upper coolant hose off. The coolant may be trickling out, and you will likely get hit with a large, hot, steam bubble. Keep your face away! Wait for the coolant to come pouring out full tilt. Then push the upper coolant hose back on.
6) Replace the clamp into the original grooves on the hose
7) Top off your coolant res.

The bubble will very likely be gone.

I use the second crazy method if a steam bubble gets stuck in the heater core. I find that particular spot is tricky to clear air bubbles out of.

....

Option 3

If you have the special equipment, you can pull a vac on the coolant ball and suck all the air bubbles out of the system


----------



## .:RyouExperienced (Sep 19, 2005)

Got ya. I will try this sometime this week before I drop any more $$$ into parts that aren't broken. 

I have never heard of the air bubble issue before. After the accident I could see how this could happen though. How does this problem usually occur?

Thanks again for the help Groggory.


----------



## RabVr6 (Nov 28, 2011)

.:RyouExperienced said:


> Any update on whether your FCM checked out RabVr6?
> 
> My scenario:
> 
> ...


I been away on business for almost a month. But I ordered a new fcm, my brother installed it, and told me it didnt change anything. Now I am scratching my head :banghead:


----------



## jason bouchard (Aug 25, 2005)

01 audi tt 225 amu 


so my fans dont kick on till 98c and sometimes it can get up to 100c or more while really beating on the car. This just started the other day when I replaced my fuel filter (and pulled the battery terminals off) 

I'm thinking maybe the fan switch is bad ? only kicking in at the high temp switch and not the low ? 

I ordered a new lower temp fan switch thinking it might help but I haven't gotten it yet so I'm waiting to try it


----------



## groggory (Apr 21, 2003)

jason bouchard said:


> 01 audi tt 225 amu
> 
> 
> so my fans dont kick on till 98c and sometimes it can get up to 100c or more while really beating on the car. This just started the other day when I replaced my fuel filter (and pulled the battery terminals off)
> ...


 You can test the operation of your fans (and related wires and electronics) by jumping the fan switch pins. One way it will operate the low fan. One way it will operate both fans. The fan switch pinout and how to jumper it is listed earlier in this thread.


----------



## jason bouchard (Aug 25, 2005)

hmm, my fans never operate idependently its always both or none but I think they will go on slow speed or high speed (if they were working on both speeds) doesnt the low speed kick on at a lower temp ? 

Thx


----------



## groggory (Apr 21, 2003)

jason bouchard said:


> hmm, my fans never operate idependently its always both or none but I think they will go on slow speed or high speed (if they were working on both speeds) doesnt the low speed kick on at a lower temp ?
> 
> Thx


 My bad.... 

Yes, when you jump the fan switch you will turn both fans on. One settings turns them both on low. One setting turns them both on high. 

Low speed kicks on at a lower temp than high speed.


----------



## jason bouchard (Aug 25, 2005)

groggory said:


> My bad....
> 
> Yes, when you jump the fan switch you will turn both fans on. One settings turns them both on low. One setting turns them both on high.
> *Nah its okay audi/vw do so many different things for each car its confusing . . . this thread is great btw, I very much appreciate you helping all of us out
> ...


----------



## turbo2.24.1990 (Jun 2, 2008)

I noticed that sometimes when at a stop light my temp guage would start to creep over 190, and after observing the fans for awhile I noticed that I haven't seen the large rad fan on the drivers side come on slow speed at all. If the fans did come one it was always together and on the high speed. 

I did the diagnostic test-everything checked out except for steps 8 and 9. I'm not familiar with a duty cycle meter, can anyone elaborate on what they are, and where to get a decent one? And also, on step 9 I wasn't getting 11 volts at pin 3 on the 14 pin connector, even when the car was holding at 2500 rpms-what does this mean?


----------



## turbo2.24.1990 (Jun 2, 2008)

bump


----------



## slappi2u (Oct 14, 2010)

*Fan issues*

Ok so when the A/C is on the big fan runs till the engine temps is up then kicks off. Small fan runs when its suppose to. When driving slow or in traffic the temp rises but I don't overheat but its close. The large fan never comes back on. When running the heat, Both fans run like they should switching from low to high speed. From reading the posts I was thinking FCM but now I am thinking temp switch on the rad. Any idea's? :banghead:


----------



## slappi2u (Oct 14, 2010)

"I noticed that sometimes when at a stop light my temp guage would start to creep over 190, and after observing the fans for awhile I noticed that I haven't seen the large rad fan on the drivers side come on slow speed at all. If the fans did come one it was always together and on the high speed. 

I did the diagnostic test-everything checked out except for steps 8 and 9. I'm not familiar with a duty cycle meter, can anyone elaborate on what they are, and where to get a decent one? And also, on step 9 I wasn't getting 11 volts at pin 3 on the 14 pin connector, even when the car was holding at 2500 rpms-what does this mean?""

In a nut shell I am having the same issue.


----------



## turbo2.24.1990 (Jun 2, 2008)

Well first-do what you can with the diagnostic at the beginning of the thread. First thing I would do would be check your fans to make sure there's nothing funky with the motors-they should work at both high n low speed. If they both check out, replace the rad temp switch-its like $10 free shipping at mjmautohaus.com, and its an easy maintenance thing that you should do eventually anyway. 

If you replace your rad temp switch, and your problem still exists-like mine does, it's probably the FCM. However, it could also be a fault in the associated wiring, or something with the ac. If you want to make sure its nothing else but the FCM before you shell out $100 for it, do the ac diagnostic posted by pattrick and check over all the wiring and connections to and from the FCM for any physical damage.


----------



## slappi2u (Oct 14, 2010)

Yes both fans work on hi/low speeds. going to order fan control switch tomorrow and hope this fixes the issue also. Thanks also for the great info.


----------



## .:RyouExperienced (Sep 19, 2005)

Update:

Just wanted to let anyone who is interested know that after flushing my system and changing out the thermostat my _car no longer overheats!_

I'm guessing it was either an air bubble or a faulty switch that was preventing the hot coolant from making it's way through the radiator. Now that the thermoswitch is getting hot, the fans work properly as well. Thanks to all who helped ...especially to you groggory :beer:


----------



## The Kilted Yaksman (Oct 31, 2000)

Read through most of this, but I am unsure where to go from where I am. Let me give you the basics.
2001 Jetta WE. Manual A/C controls. 140k miles. 
No problems with the A/C until this summer.
The A/C only occasionally blows cooler than ambient.
All 4 fan speeds seem to work correctly.
There seems to be appropriate amount of refrigerant in the system.
The A/C clutch engages and the compressor turns.
The radiator fans only run at high speed when the A/C is on.
When the fans are jumped at the fan switch connector they run at both speeds.
The fan control module was replaced with a new unit, and the fans ran at the proper low speed, and it seemed to be blowing cold, but only for about 45 minutes. Now it is back to where it was before.

Fan switch?
Wiring problem?
Something else?
Short of component R&R, or car stereo installations, I am somewhat of a neophyte when it comes to auto electronics. Any assistance is appreciated.


----------



## groggory (Apr 21, 2003)

I would recommend taking it in for an A/C service.


----------



## pIOUs (Feb 17, 2013)

The Kilted Yaksman said:


> Read through most of this, but I am unsure where to go from where I am. Let me give you the basics.
> 2001 Jetta WE. Manual A/C controls. 140k miles.
> No problems with the A/C until this summer.
> The A/C only occasionally blows cooler than ambient.
> ...


What was the solution for this? I suspected temperature flapper or flapper motor should be checked.


----------



## rcvwvortex (Aug 13, 2013)

*How do you get the electrical harness out of the way?*

There's a bunch of electrical harness below the battery tray. They are pretty tight. How did you move it out of the way to gain access to the fan controller module mounting bolts? Please check on link below for reference. Thanks!

http://forums.tdiclub.com/showthread.php?t=281684


----------



## fookurvtec (May 23, 2012)

hey hope this thread is still good because i am having issues with my mk4 1.8t GLI. my big fan wont turn on when it needs to already swapped FCM and thermostat and nothing fan turns on when a/c is on but that is it please help losing my mind and h20 is 2 weeks away!!!!!!.
also have coolant ball delete not sure if this has anything to do with it.


----------



## Islandsilvia (Sep 8, 2010)

I need some help with my control module. 

All tests were done that were explained previously. There is power going into the module, however only 1 wire to power the switch or fan is not getting power. I thought it was the fcm but I got a brand new one and tried it out, both fans still don't kick in. Not sure if you guys have ever heard anything like that. I have no a/c in my car as there is a hole in my a/c line. my car is rhd btw. 

So do you guys have any ideas about the fcm and no power coming out of it just to that one wire?


----------



## NOMAD323 (Apr 23, 2014)

*1.8T Engine will overheat at idle when A/C is turned on*

I have had this problem for some time now. Haven't really looked into it but now that it's getting warm outside I figured I would fix the problem. So here is exactly what I am experiencing. When I turn my A/C on, it will blow cold up until my engine is at operating temp and I'm at idle. That's when my engine will start to overheat and my A/C will start to go warm and muggy. So judging that the first thing I think is that my Aux fan must not be working correctly. Just wanted to know if there was a common sensor or connector that seems to crap out to cause this or not. 

Thanks guys! 
DC


----------



## groggory (Apr 21, 2003)

NOMAD323 said:


> I have had this problem for some time now. Haven't really looked into it but now that it's getting warm outside I figured I would fix the problem. So here is exactly what I am experiencing. When I turn my A/C on, it will blow cold up until my engine is at operating temp and I'm at idle. That's when my engine will start to overheat and my A/C will start to go warm and muggy. So judging that the first thing I think is that my Aux fan must not be working correctly. Just wanted to know if there was a common sensor or connector that seems to crap out to cause this or not.
> 
> Thanks guys!
> DC



The tidbit about your engine overheating is what you should focus on here.


----------



## NOMAD323 (Apr 23, 2014)

groggory said:


> The tidbit about your engine overheating is what you should focus on here.


The engine will run fine and not overheat unless my A/C is turned on. With that being said I believe it has to do with the cooling fan. Maybe the coolant temp sensor or rad fan switch. Wasn't sure if someone had a similar issue or not.


----------



## Mindfault (Feb 2, 2010)

Subbed


----------



## petreyg (May 12, 2008)

*Ac not working. Tested fan thermo switch*

When testing the fan thermo switch and shorting connection 1 and 2 no fans come on. When shorting connections 2 and 3 both fans come on. When shorting connections 1 and 3 both fans come on. All fuses are fine. How do I jump 12 volts to the ac clutch to test the compressor? I've started the car. Turned on ac. Shorted thermo switch to turn fans on. And still no ac. Clutch does not engage. Any help is appreciated.


----------



## conleyp08 (May 31, 2014)

OK just had the exact same problem I changed the control module and the connectors under the battery because they we unplugged and corroded when I got the car but it didn't fix it.. When I got to checking fuses I found there was 7.5 amp mini fuse blown I replaced and my a/c quit acting up my brake light quit coming on and off depending on if the recirculation switch was on or off and actually my daytime headlights started working off my e brake finally.. not sure if this helps anyone but I did see a couple posts have the same weird issues as I was so hopefully it helps someone


----------



## Brake Weight (Jul 27, 2006)

Tests 1-6 are fine. 

Get to 7, the ambient temp switch and it's not showing continuity. Swap out the sender with the one from the bumper it's still not showing. Cut a wire and jump the harness for the temp sender, in the rain tray, and now I have continuity. 

Skip test 8. 

Test 9; I have voltage, but it's bouncing around 4-7v. 

(Test 10) Checking pin 10 for 12v output to compressor coil. I have the same results as test 9 with voltage bouncing around 4-7v. 

Both fans work as they should. 


I have not checked anything aside from this. 

Here's the backstory. I drove the car to the airport and the AC was nice and cold. I parked it in the outdoor parking for right at a month. When I get back, I check the tires and oil level. Roll it over a few times to 'prime' everything with oil then let it idle while I toss my bags in. I get in, turn on the AC and it started blowing cold for a few seconds but by the time I backed out of the spot to head to the booth to pay the nice lady it was blowing hellishly hot. It was pushing 100* that day, so the parking lot was well above that. 

Drive home for 2 hours like this...sweating balls. I check it out the next day and find that when I had rebuilt my motor and re-installed it, I had broken the tab on the harness connector for the small fan. It had apparently fallen off in the parking lot of the airport as soon as I backed out. I had driven home in this sweltering heat, but the car did not overheat so I thought not so much of the fans working properly. 

So I plug this back in thinking the AC will work once again, but it doesn't. Leading me to the results above and no indicators of anything totally wrong or failed. 

Whiskey
Tango
Foxtrot?


----------



## KingOf_Pain (Aug 13, 2014)

The FCM have sure dropped in price from 2008 at $100, to $25 at AutohausAZ. Picked up a "AC thermal cutoff switch" also, but I can not find it on my 2001 2.0L AEG. I have also found some info on the net that did not list the AEG having that sensor. Anyone know for sure?

Thanks in advance,
Brian W


----------



## KingOf_Pain (Aug 13, 2014)

My daughter's 2001 Jetta 2.0L AEG has intermittent AC issues. Thanks for the great info. I will check voltages at the FCM and test the fans as described above. I also have no idea on measuring duty cycles, but I can google that.
Anyone near Hanford, CA have a VAG-Com?


----------



## nrotteveel (Jan 27, 2015)

Do all of you buy OEM equipment to replace these parts? I have to check my system since my large fan doesn't turn on, but the small one does. So if it is the large fan, have you guys all used the OEM part for $$350-400 or do you buy an aftermarket. Given this is just a fan, I was looking at an aftermarket fan since it is half the price. But wondering what people have found.

If it is the temp fan control sensor, I will go OEM. But does everyone recommend that the OEM FCM be used or have folks used some of the aftermarket. For the electronics I typically stay OEM, but wanted to hear what people have used and if they have been any success or failures with aftermarket. Thanks


----------



## nrotteveel (Jan 27, 2015)

Hot as can be outside. Not able to get under car at these temps, i.e. 110. But was able to see that the small fan kicks on for both the AC and for radiator temp. With the car off and the small fan running, I noticed that the large fan my have clipped an electrical housing. Just pushed on the electrical housing and just happened to spin the fan by hand. It started to spin on its own, but at a very low speed and the fan was wobbling a bit.

So not sure if there is electrical housing and wires there in damaged, but they do come from the fan assembly and up towards the battery. 

Looks like I need a new fan no matter what since the fan is out of balance, but need to do a more thorough check when it cools down later tonight, hopefully.


----------



## nrotteveel (Jan 27, 2015)

It was the large fan, but it did scare me after I removed it. When it was in the car, I put direct power to the fan and it did nothing. Removed it from the car and tried again and it kicked on for both high and low. Removed it from the shroud and did a continuity check, nothing. Tried power to it again, nothing. Put in a used fan I picked up at the junk yard (full shroud with both fans with 6 month guarantee for $100) and now it works like a charm. We will see for how long. But all I can say is that the original fan did not give consistent test results which is always fun during trouble shooting.


----------



## boardmanrice (Sep 13, 2015)

*gti 337*

I'm not getting power from my number 9 pin switched ignition on the T14 plug fan control module where does that wire go? And what does this even mean ? I stoped further troubleshooting when I found out I'm not getting power to the t14/9 pin please anything will help!


----------



## Tutorman04 (Jun 3, 2015)

I just replaced my fan housing unit with aftermarket I found on E-bay 120 shipped they work just fine. My fans still don't turn on when A/C is pressed and fan sw on. So my problem is still a problem. I got 2 different aftermarket FCM's and nothing then got one from a bone yard and nothing. I went through this testing from the start of this thread. I even went through and cleaned all the grounds under the battery. Same results. I found a local vw guy that's going to look at it for me next month. I'm sure I'll feel real stupid when it turns out a simple fix.:banghead:


----------



## nrotteveel (Jan 27, 2015)

Tutorman04 said:


> I just replaced my fan housing unit with aftermarket I found on E-bay 120 shipped they work just fine. My fans still don't turn on when A/C is pressed and fan sw on. So my problem is still a problem. I got 2 different aftermarket FCM's and nothing then got one from a bone yard and nothing. I went through this testing from the start of this thread. I even went through and cleaned all the grounds under the battery. Same results. I found a local vw guy that's going to look at it for me next month. I'm sure I'll feel real stupid when it turns out a simple fix.:banghead:


Do the fans come on at high coolant temp? if the fans don't come on ever, I sure hope you checked the main fuse on top of battery.


----------



## nrotteveel (Jan 27, 2015)

Okay, large fan is out again. Bought a used VW one from salvage yard.

I had been experience some groaning/Humm as can be heard in this video https://youtu.be/t4ypIkkH0CQ . It usually happened while at a stop light and disapaited as i drove. Which should have been a clue it was the fan.

With the AC on, the small right (passenger side) fan goes on low. Large left (drivers side) fan does nothing. When the small fan eventually kicks to high, i can spin the large fan by hand and it will catch and start going on high on its own. When the fans move back to low speed, both fans still work. And when it kicks back to high, both go to high.

If i turn AC off and let fans stop, i then turn on AC again and again the large fan will not spin. But can get it started by starting it by hand.

I will get car on jacks this weekend and jump the connector at radiator temp sensor to make sure it is the fan.

Since it is only one fan, i'm having a hard time thinking it is something other than the one fan that is out and not a sensor or fan control module. 

Any other opinions?

Also, trying a meyle fan from Pelican parts. Mistake?


----------

