# Radiator fan does not run, 1996 Jetta w/AC & stick



## psparky (Dec 29, 2008)

I disconnect fan connector and there is no power on any of the leads, key on or key off. I checked the fuse and it is good and there is power to it. There are three wires to the fan motor, red, brown and red/white. Can I splice into the red with a powered fused lead and see what happens next? On my old Rabbit the fan came on when the temp sensor closed and completed the ground. Is there a radiator fan relay?


_Modified by psparky at 8:25 AM 10-13-2009_


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## psparky (Dec 29, 2008)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (psparky)*

Well a little online searching shows that a radiator fan control relay is available for this car, Amazon.com for $72, probably a good place to start. Anyone know where this relay is located?


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## 2pt. slo (Jan 4, 2004)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (psparky)*

read through dan j reed's site before you start throwing parts at it blindly. this site will have a few tests you can do to help diagnose your problem
http://faculty.ccp.edu/faculty...x.htm


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## Robert Roberts (Jan 30, 2009)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (psparky)*

^^^^listen to the good advice above.
It helps if we know what kind of car/engine you are working on.
If you are going to keep the car for a while and work on it yourself, you may want to get a Bentley repair/service manual for your car (they have their quirks, mainly the index is a PITA, but are the best available without sourcing actual VW service manuals ($$$).)


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## psparky (Dec 29, 2008)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (2pt. slo)*

Thanks a bunch, reading now, that's the kind of advice I was looking for, I have the Bently on order


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## germancarnut51 (Mar 23, 2008)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (psparky)*

The MKIII has a thermofan switch on the radiator, the same as a MKII. You can try shorting it to see if you can get the cooling fans to run the same way.
The power for the cooling fans (only one fan actually has a motor, the right side fan is driven off a narrow serpentine fan belt connected to the left side fan) works the same basic way as a MKII, with the exception of the additional cooling fan module mounted on the car's left side inner fender below the hood switch for the alarm system.
You can also try switching on the ac, as the fans should run anytime the ac is on.


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## 2pt. slo (Jan 4, 2004)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (germancarnut51)*

the link i provided above says what you stated. http://****************.com/smile/emthup.gif


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## psparky (Dec 29, 2008)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (germancarnut51)*

Did not have time to paper clip jump temperature sensor but will today. I like the idea of turning on the AC and see what happens. I guess if it runs it says the fan is ok but the temp sensor and the control relay and some of the fuses are still in question?


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## psparky (Dec 29, 2008)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (psparky)*

Started troubleshooting: Fuse 19 and fuse 6 are 30 amp and are good, fuse 4 is empty and owners manual says it is not used. Disconnected temp sender connector and jumped the pins, the fan runs on low speed but not on high. Turned on AC and it does not trigger any fan action. Tried removing the sensor but could not get it out, very tight area maybe a 1 3/16 deep socket but not sure. Channel locks or adjustable can't get in there. Off to borrow large socket, any hints, let me know.


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## dan0954 (Mar 4, 2009)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (psparky)*

On mine and others when doing that test, you need to have the key on for the high speed test to work. I'm not sure if you had the key on as the link really does not say to for the high speed test.


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## psparky (Dec 29, 2008)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (dan0954)*

Thanks Dan, key was off so I will double check. Got some deep socket assortment to try for a fit to the sensor but pretty nasty outside today.


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## psparky (Dec 29, 2008)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (psparky)*

Got the sensor out with a 30mm but that is actually a little bit large, not sure what size it really is, ordered new sensor on-line.
But my bigger question is what the function of the FCM? If you can get the fan running by jumping the radiator temperature sensor it seems like the FCM is out of the loop.


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## psparky (Dec 29, 2008)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (psparky)*

Update: Turned the key on and shorted the contacts in the temperature sensor plug and the fan runs on high speed. Turned AC on with key in on position and the fan runs, ALL GOOD. Installed new temperature sensor, ran the car for 10 minutes, drove it for 10 minutes, refilled the tank and let it run for about 10 minutes and the coolant started to boil but no fan action, put radiator cap on and continued to run but still no fan action. After some thought I think I should put the ohm meter across the contacts on the sender and see if either set has closed when the car is hot.


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## dan0954 (Mar 4, 2009)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (psparky)*

That's what I did as mine was doing the same thing. I found at the time that it did not make the connection until the line past half. After a few spirited drives now they kick on a hair passed half. Then I stuck a temp. probe in the globe and it was only reading 200.
I did have a bad t-stat that was replaced and I think I still had air in my system.


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## psparky (Dec 29, 2008)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (dan0954)*

Dan, do you think I have air trapped in the system?


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## dan0954 (Mar 4, 2009)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (psparky)*

That was just in my case as I had just done the t-stat, I'm not sure about yours. Using the meter will help answer if and when the switch is telling the fan to turn on. The temp. probe just helped me confirm the the temp. gauge was in the area it should be.


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## psparky (Dec 29, 2008)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (dan0954)*

Everything changed, go figure. Checked the radiator sender when the car was hot and there is continuity between two pins (high speed) but fan does not run. Now unplug sender and paper clip jumper the contacts and now the fan does not run. I let the car cool off and sender never opens up, whats with that, new sender is bad! Recheck sender connector with paper clip and the fan will only run on low speed with key off and will not run on high speed with key on. Tomorrow's another day.


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## dan0954 (Mar 4, 2009)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (psparky)*

Did you happen to let it boil over on to the FCM?


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## psparky (Dec 29, 2008)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (dan0954)*

The red wire on the radiator sensor had some broken insulation and you could see the copper strands, I cut the connector out and spliced in one from the junk yard. The radiator sensor was now open for high and low as the car was cold. Started it up with OBD scanner and monitored the coolant temperature and the fan came on at 204F and turned off at 194F, I almost fell over, go figure. Will drive around for a few days before giving it back to my daughter, Brooklyn seems to bring out the worst in the car.
The OBD scanner seems to show the car runs about 160F while moving on the highway, it goes to about 170F while sitting at a light for a few minutes. This is 60F ambient conditions. The dashboard gauge does not match the OBD readout very closely but it never goes over straight up/down.


_Modified by psparky at 7:23 AM 10-27-2009_


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## psparky (Dec 29, 2008)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (psparky)*

Dan, having the FCM right under the globe does seem like an excellent location (NOT) for destroying the unit with hot coolant.


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## dan0954 (Mar 4, 2009)

*Re: Radiator fan does not run, 1996 Jetta w/AC & stick (psparky)*

So it was a bad connector, at least you got it fixed. http://****************.com/smile/emthup.gif


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