# Fuel Gauge Stuck on Full



## mister-j (Apr 20, 2016)

The fuel guage is stuck on full but the miles to empty is slowing going down but doesn't seem accurate. Is this more likely a guage issue or a sensor issue.
Is there a thread that tells how to fix the sensor or other related help?


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## G'D60 (Mar 11, 2002)

It will likely be your sender. common failure on our cars. they get gunk built up on them and they won't read properly. Lite1979 is going to take some pictures when he cleans his over the next few weeks. See thread below:

http://forums.vwvortex.com/showthread.php?7315865-FAQ-for-cleaing-the-fuel-level-sender


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## mister-j (Apr 20, 2016)

Thanks, I thought it was. I found some great step by step instructions to check and maybe fix the sendor unit. I asusme there are no rules against posting links to other fourms - just wanted to check before doing so.


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## 20v master (May 7, 2009)

G'D60 said:


> It will likely be your sender. common failure on our cars. they get gunk built up on them and they won't read properly. Lite1979 is going to take some pictures when he cleans his over the next few weeks. See thread below:
> 
> http://forums.vwvortex.com/showthread.php?7315865-FAQ-for-cleaing-the-fuel-level-sender


Dang, you're still waiting on pictures? Put some gloves on, and go get to it! Like I said, it's really self explanatory when you get the pump assembly out.


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## G'D60 (Mar 11, 2002)

mister-j said:


> Thanks, I thought it was. I found some great step by step instructions to check and maybe fix the sendor unit. I asusme there are no rules against posting links to other fourms - just wanted to check before doing so.


post link. would help others in here i'm sure.

20V. Haven't done it yet, I'm in no hurry. I like to see what i'm getting into before I get dirty. Thats just me.


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## TheDeckMan (Sep 26, 2004)

G'D60 said:


> post link. would help others in here i'm sure.
> 
> 20V. Haven't done it yet, I'm in no hurry. I like to see what i'm getting into before I get dirty. Thats just me.


Its really straight forward, the tricky part when pulling the pump out and putting back in is the saddle line that clips in, getting everything to go together is a bit of a test of patience and not an exercise in force. It helps to wear a respirator and do it out side to deal with the fumes.


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## 20v master (May 7, 2009)

G'D60 said:


> post link. would help others in here i'm sure.
> 
> 20V. Haven't done it yet, I'm in no hurry. I like to see what i'm getting into before I get dirty. Thats just me.


Remove access panel with three screws. Remove fuel lines, and harness to the pump housing. Unscrew retaining ring. Lift out pump basket assembly. It looks like this:










The arm float should be obvious. It looks like this, on the side of the pump assembly.










Lightly clean the metallic contacts that are on the path of the arm float. Moving it through it's range of motion should make it obvious what you're doing. This really is very simple. :thumbup: As said, have a bucket handy to put the pump assembly in when you lift it out of the tank. And wait until you're low on fuel or it'll be really messy. Make sure the Oring isn't pinched when you reinstall the retaining ring.


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## lite1979 (Sep 9, 2005)

Honestly, I had every intention of doing this today and taking a ton of pictures, but it's raining 

Personally, I've never taken this pump out, nor have I removed the auxiliary pump on the left side, so I'm interested to check them out. Crossing my fingers for dry weather tomorrow, but I'll probably wait until Wednesday. 

I should also mention that the first time this happened to me, it was after the car sat for several months, and I was able to get the gauges reading accurately after a few full-tanks with Chevron Techron added before filling up, then again every oil change, but it's not helping anymore.


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## G'D60 (Mar 11, 2002)

Great pix 20V thanks, doesn't look as daunting now. Lite, i've tried using Techron on several tanks of gas and nothings changed. Ever. Pretty sure this is my only solution. Hope you get some good weather. A comprehensive FAQ on this subject is needed. 

Thanks again fellas!


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## lite1979 (Sep 9, 2005)

I'm finally doing this today. My lower back is killing me! Main pump is out. Full write-up and how-to coming later tonight..


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## mister-j (Apr 20, 2016)

lite1979 said:


> I'm finally doing this today. My lower back is killing me! Main pump is out. Full write-up and how-to coming later tonight..


Was going to attempt it this weekend but will wait for your write-up and photos.


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## mister-j (Apr 20, 2016)

Decided to try it and got pretty far but then got stuck as I wasn't sure how to unhook the lines to the secondary pump. BTW, I could see why my guage wasn't working. The float on the arm of the sensor is not even on the arm - it looks like it snapped/broke off. Do these things break off or come loose? Has this happened to anyone and can it be put back on on do you have to buy a new fuel pump or can I buy just the sensor with the float arm?

Anyway, to get it out completely what needs to be unhooked from the secondary pump and how. I can see there is a fuel line - see pic below but tried to get the connector off but wouldn;t go and I didn't want to break anything. How do I get this off - assuming it needs to be disconnected?




Here are few pictures and some procedures that worked for me to at least get at the fuel pump.

Before removing the pump. Probably never taken out before - like 2mm of dirt built up


After cleaning it up. Didn't want to get dirt in the tank


Pump exposed


A few things worth noting that I found:

1) I took out the fuse for the fuel pump #28 and then I started the car so it would drian the pump of fuel. That worked great because when I took the hoses off I barely had any fuel come out.

2) It took a lot of force to loosen the retaining ring. Tried block of wood but the wood was to soft. This ring it built solid so I used a big screwdriver and rubber malet. Once I saw it budge, I knew i was going to get it loose.

3) The electrical harness came off easily but the fuel connectors were tough. I used a screwdriver to push at the bottom of the cip and then it came off pretty easily. Glad I didn't break it.


Lite1979 - how did it go? Anxcious to see how you made out.


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## mister-j (Apr 20, 2016)

Found this picture (in another thread) of the whole fuel pump sending system which helps a lot. So what I can see is 3 connections - two lines, and one electrical?

Now I just need a little guidance in the procedure to take the connectors offf.


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## lite1979 (Sep 9, 2005)

Fixed: http://forums.vwvortex.com/showthre...Mk1-TT-lots-of-photos&p=96055530#post96055530

You'll see in my write-up that the male part of the transfer tube is the side near the main pump. It's about as stubborn as the feed and return connections on top of the main unit. The other tube doesn't require disconnection, as it's just attached to the plastic piece that clips between the sending unit and the pump assembly.

The electrical wires disconnect pretty easily. Just squeeze the one side and pull the other part away. There should be a zip tie holding it to one of the transfer tubes so it'll be easy to fish back through.


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## mister-j (Apr 20, 2016)

Great stuff. Congrats on getting it done.

Can you clarify a couple of things before I try it agian. 

Did you remove the drivers side unit first before you disconnected any of the hoses on the pump side?

How many connections are there to disconnect on the pump side?

You show a picture where you say this is the view after disconnecting but I don't see it disconnected where I thought?

Thanks again for posting this - gives me some more confidence to try it again.


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## lite1979 (Sep 9, 2005)

Thanks! To answer your questions:

I removed the main pump/sending unit first (passenger's side). You can't really remove the driver's side sending unit until you disconnect the transfer hoses and sending unit wire on the driver's side.

There are three things to disconnect:

1. The tube with the disconnect fitting - squeeze the fitting, wiggle the tube, eventually it will come out. The part coming from the main pump goes into the fitting.

2. The electrical wires that go to the other side - you'll need to get both hands on there to get the harness apart, but it's not too tight. Just squeeze the two tabs on the one side and pull on the other.

3. The white(ish) plastic thing that guides the return transfer down toward the bottom of the main unit - just lift up on it, and it should wiggle out pretty easily.

That's not the best picture. You can see the male side (pump side) of the tube, and directly below it is the female part (the retaining clip).



mister-j said:


> Great stuff. Congrats on getting it done.
> 
> Can you clarify a couple of things before I try it agian.
> 
> ...


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## mister-j (Apr 20, 2016)

That helps. So in my picture here is this where you have to squeeze to get the connector apart?


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## lite1979 (Sep 9, 2005)

Yes. The part on the left will come out. Mine was twisted so I couldn't see the part that you press in, but your picture makes it obvious.


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## mister-j (Apr 20, 2016)

Okay, thanks. I'll have to use a little more force then because I couldn't get it to come apart.


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## lite1979 (Sep 9, 2005)

Yes; pinch on the connector, and pull the left part out (the part that's cut-off in your photo). This was the most difficult part of the removal for me, and I had to twist and wiggle it a little bit before it finally came free.


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## mister-j (Apr 20, 2016)

*Diagnosis Completed*

My gas was finally low enough (almost empty) to pull the fuel pump. Unfortunately for me the sensor was not the issue - must be the fuel gauge. I pulled the pump again and this time got it all the way out (thanks to information in this thread) and tested the fuel sensor before cleaning it and it appeared to be working perfectly with the resistance close to within specs. which is between 59 low and 282 full. I cleaned the sensor anyway and the resistance readings did not change. Unfortunately you have to partailly pull the fuel out to check the resistance unless you know how to do it at the cluster. Which in hindsite is probably what I could have done and saved the hassle of pulling the fuel pump out. One thing I did notice that the hose on the bottom of the tank where the fuel comes in (when pump gas in the tank) popped out of the clamp, so I put that hose back in the plastic clamp (which probably doesn't effect anything but did it anyway).

Anyway, looks like I will have to get my gauges rebuilt. So again my situation is when I fill the tank the reading goes way over full - may be a clear sign of a guage issue - not sure?


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## lite1979 (Sep 9, 2005)

Reading over full definitely sounds like a gauge problem.


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## MCPaudiTT (Nov 26, 2006)

mister-j said:


> Found this picture (in another thread) of the whole fuel pump sending system which helps a lot. So what I can see is 3 connections - two lines, and one electrical?
> 
> Now I just need a little guidance in the procedure to take the connectors offf.


Great pic, thanks.


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## mister-j (Apr 20, 2016)

Clearly has the symptoms of a sensor issue (not reading fuel level correctly) so I was a bit surprised it wasn't the dirty sensor problem. The guage stays on overfull for about 200 miles before it moves and then it drops very quickly at some point. Still sounds like a sensor issue to me but I tested and cleaned both sensors so I have to assume its a guage problem at this point.

Did anyone have these exact symptoms where it wasn't a guage issue? I just realized that my resistance readings were not exactly within spec but the sensor guage was doing was it was suppose to as you moved the fuel level arm up and down, plus I cleaned it and the readings didn't change so at this point I'm concluding its the guage.


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## G'D60 (Mar 11, 2002)

What are guys seeing on your guages to think this is a level sender issue? For me it was my fuel level was always read full. Even past full for the first 2/3 to 3/4s of a tank. After that it would fall to 70-80 full (when I know theres less than a quarter tank left) that leads me to believe there is gunk on it that needs to be cleaned. Was this what other guys were seeing?

I'd hate to tare this thing open and not have an issue on the level sender. 

Whats the climate control trick/readout guys are using? is there a VAGCOM mblock I can read?


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## mister-j (Apr 20, 2016)

G'D60 said:


> What are guys seeing on your guages to think this is a level sender issue? For me it was my fuel level was always read full. Even past full for the first 2/3 to 3/4s of a tank. After that it would fall to 70-80 full (when I know theres less than a quarter tank left) that leads me to believe there is gunk on it that needs to be cleaned. Was this what other guys were seeing?
> 
> I'd hate to tare this thing open and not have an issue on the level sender.
> 
> Whats the climate control trick/readout guys are using? is there a VAGCOM mblock I can read?


This is exactly what my symptom is. ie. fuel level was always read full. Even past full for the first 2/3 to 3/4s of a tank. After that it would fall to 70-80 full etc.

I don't know about VAGCOM having a fuel sender level reading? The sender works on change in resistance. Low resistance when float level is in low position and higher resitance when full (or vice versa - I can't remember). But if the sensor resistance changes as you move the arm up and down - that should mean its working and sending the right level information to the guage. You can use a multi-purpose meter to measure ohms (ie. resistance). If the readings don't chnage that means the sender is gummed up (and cleaning appears to fix it) or it's broken.


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## lite1979 (Sep 9, 2005)

I think you can test the gauges with Vag-com, but I haven't done it myself yet. 

In my case, when I was sure that my sending units were messing up, I would run out of gas when it said I had twenty miles left on the tank, or I'd go 150 miles after filling up, and it would still say I had more than 3/4 of a tank.

Sent from my XT1254 using Tapatalk


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## mister-j (Apr 20, 2016)

lite1979 said:


> I think you can test the gauges with Vag-com, but I haven't done it myself yet.
> 
> In my case, when I was sure that my sending units were messing up, I would run out of gas when it said I had twenty miles left on the tank, or I'd go 150 miles after filling up, and it would still say I had more than 3/4 of a tank.
> 
> Sent from my XT1254 using Tapatalk


Again that's exactly what is happening in my case but cleaning the sending unit resistance coil (both tank sides) did nothing to fix my problem. Still a little puzzled about that because it seems to work for so many people.


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## G'D60 (Mar 11, 2002)

Do you have any other cluster issues? like dead pixels? My cluster is perfect (knock on wood) other than this fuel level issue. at this point i'll likely pull the pump and check things out to be sure.


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## mister-j (Apr 20, 2016)

Yep, typical missing pixel issues on the control panel but everything else seems to be working fine.


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## 20v master (May 7, 2009)

mister-j said:


> Again that's exactly what is happening in my case but cleaning the sending unit resistance coil (both tank sides) did nothing to fix my problem. Still a little puzzled about that because it seems to work for so many people.


If it's the sending units, the gauge needle will mirror the temp gauge when the cluster turns off/is powered up. I've had the senders that needed to be cleaned before in my 180Q, but the gauge behavior was a lot more erratic. Like I'd be down to about 1/4 tank, and all of a sudden the tank would read full for a day or two, then back to normal. Or vice versa, I'd have about 3/4 of a tank, and it would suddenly start beeping the low fuel warning and tell me the tank was empty. In my current daily 225 however, the gauge seems to read somewhat accurately, but it's like the gauge isn't calibrated/ is offset. It reads WAY past full when I fill up, and stays there for most of the tank, then about 1/4 tank left it starts coming down, and would be ~1/2 tank when the car would run out of gas. My miles to empty still functions normally, as does the low fuel warning. However, like I said earlier, when the cluster is switched off, the gas gauge needle doesn't return to the far left. Hence why I think this is an issue of the gauge stepper motor having gone bad.


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## G'D60 (Mar 11, 2002)

20v master said:


> If it's the sending units, the gauge needle will mirror the temp gauge when the cluster turns off/is powered up. I've had the senders that needed to be cleaned before in my 180Q, but the gauge behavior was a lot more erratic. Like I'd be down to about 1/4 tank, and all of a sudden the tank would read full for a day or two, then back to normal. Or vice versa, I'd have about 3/4 of a tank, and it would suddenly start beeping the low fuel warning and tell me the tank was empty. In my current daily 225 however, the gauge seems to read somewhat accurately, but it's like the gauge isn't calibrated/ is offset. It reads WAY past full when I fill up, and stays there for most of the tank, then about 1/4 tank left it starts coming down, and would be ~1/2 tank when the car would run out of gas. My miles to empty still functions normally, as does the low fuel warning. However, like I said earlier, when the cluster is switched off, the gas gauge needle doesn't return to the far left. Hence why I think this is an issue of the gauge stepper motor having gone bad.


This is interesting and what I have noticed as my issue too. I can't recall how the guage reacts when the car is off, i'll have to look at that going home. Were you able to remedy the issue? where would the stepper motor be?


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## mister-j (Apr 20, 2016)

20v master said:


> If My miles to empty still functions normally, as does the low fuel warning. However, like I said earlier, when the cluster is switched off, the gas gauge needle doesn't return to the far left. Hence why I think this is an issue of the gauge stepper motor having gone bad.


Logic would dictate that it must be a guage problem if the "miles to empty" and the "low fuel warning" function correctly. ie. can't be a problem with the sending unit. This is my case too and I could have saved the time of pulling the fuel pumps but it's okay because I did clean the sending unit and shouldn't have the problem with that being gunked up for a while now anyway. Also, if my fuel pump ever goes replacing it will be easy, now that I've done the procedure already. Thanks to to all for all the help getting there.


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## mister-j (Apr 20, 2016)

*Stepper Motor*

The stepper motor is in the guage and needs to be professionally rebuilt. Most places will rebuild and recondition the whole cluster replacing the stepper motors and LED display (pixel missing problem) and recalibrate everything. 

BTW, when I first got my car a few weeks ago, a lot of the pixels were missing on the control display but now 99% of the display is not missing pixels. Does this happen, when sometimes the pixels are missing and then they return? Just curious, as I'll be getting my full cluster rebuilt very soon anyway including replacing the LED display.


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## lite1979 (Sep 9, 2005)

Dead pixels are always dead; they don't come back. Odds are, there's a voltage problem in the cluster in your case. Mine fades to black on the left hand side after I've driven for a few minutes, and my fuel gauge still reads slightly higher when I first start the car than when I last drove it, so I suspect a bad capacitor in my case. Yours may be similar. 

Even though my cluster was built after the lawsuit days of the early mk1 TT, it's still not perfect, so I may send it out to be rebuilt eventually despite the fact that it's 99% functional.

Sent from my XT1254 using Tapatalk


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## 20v master (May 7, 2009)

mister-j said:


> The stepper motor is in the guage and needs to be professionally rebuilt. Most places will rebuild and recondition the whole cluster replacing the stepper motors and LED display (pixel missing problem) and recalibrate everything.
> 
> BTW, when I first got my car a few weeks ago, a lot of the pixels were missing on the control display but now 99% of the display is not missing pixels. Does this happen, when sometimes the pixels are missing and then they return? Just curious, as I'll be getting my full cluster rebuilt very soon anyway including replacing the LED display.


Yes, mine has lines that come and go with the seasons. Summer makes them disappear, they come back in fall, gone again in winter, and back in spring, slowly losing one or two permanently per year. I've just been dealing with the fuel gauge being off and haven't addressed it.


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## G'D60 (Mar 11, 2002)

So I noticed my fuel gauge will go to half way empty when the car is shut off. It does NOT correlate with the movement of the temperature gauge. Once the car is on it will shoot well past full. I feel like this is a stepper motor issue the more I think about it...


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## lite1979 (Sep 9, 2005)

Temp and fuel level have separate stepper motors, so fuel can be messed up independent of temp, and vice versa.

I spent hours reading about the gauge cluster issues in the early mk1 TTs, so when I had to replace mine, I knew to look at the manufacture date. I encourage you guys to check your gauge clusters for manufacture date as well.


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## G'D60 (Mar 11, 2002)

what am i looking for manufacturer date wise?


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## lite1979 (Sep 9, 2005)

They changed the cluster design or something after chassis number TRU_ _ _ 8N_ 51017389 (or at least that's what the lawsuit in UK covered up to). Not sure what year vehicle that is, but my cluster was made in '04, despite coming out of an '01 TT.

Here's the old lawsuit thread: http://www.audiforums.com/forum/audi-tt-7/instrument-cluster-lawsuit-95908/

On page 2 of this thread, they mention that the OEM manufacturer started using a corrected part for movement of the fuel and temp gauges in 2002 (many cars built in 2002 arrived as 2003 model year cars, however): http://www.audiworld.com/forums/tt-mk1-discussion-9/diy-cluster-repair-1928539/


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## MCPaudiTT (Nov 26, 2006)

It was never properly fixed. I bought a car CPO in 2003, with coverage to 2006. One week before the warranty was over, I had the cluster replaced. It's bad again...


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## lite1979 (Sep 9, 2005)

Really? What other problems have you had with the cluster? Not to get too off topic, though. Perhaps we should start a thread of gauge cluster experiences.

Regarding the original thread topic, even though my car reads the correct fuel amount after running for a while, I'm finding that when I first start my car, the fuel level seems to always be higher than when I turned it off, and it seems to be more severe every time I start the car. The left side of my MDF is faded when it's reading right, but comes in just fine when I start the car, which I think is related. I still have not experienced the jerky movement of the fuel gauge as I saw before cleaning the sending units. The fact remains that my gauge does not read correctly 100% of the time.


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## QCOUPETT (Dec 21, 2012)

*Similar issue- What do you all think?*

I have a 2003 Roadster, and the cluster (along with the fuel gauge stepper motor) was rebuilt one year ago. When I bought the car, the PO said the fuel gauge would not go past half full, and it had some pixilation, so I had it rebuilt. Everything was absolutely fine until about a week and a half ago, now when I top it off, it will not go past 3/4 full. The company that rebuilt the cluster said it's my sensors, when I asked them about a warranty on the stepper motor. I am wondering if it is the sensors, why did it take a year for this to show up. Have not run a Vagcom yet, just wondering...TIA.
John


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## lite1979 (Sep 9, 2005)

See if pulling the fuses for the fuel pump and the gauge cluster helps at all:

1. Pull fuses

2. turn key to on

3. turn key off

4. replace fuses

5. turn key on; note fuel level


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## mister-j (Apr 20, 2016)

It could be the guages or the sending unit. It does sound like in your case it's likely now a dirty sensor. I'm not sure how to test the guage but but you can test the sensor by measuring the resistance at the different float positions to see if the resistance varies and is within specs. (see previous post for factory resistance specs).


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## QCOUPETT (Dec 21, 2012)

Fuse 28 & ?
Thanks


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## lite1979 (Sep 9, 2005)

Fuses 28 and 15.


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## QCOUPETT (Dec 21, 2012)

Thnx I will try this and see what happens.


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## tt92103 (Nov 23, 2010)

Hello I am bumping this old thread.
I have the same symptoms as a couple of other posters on this thread. The fuel gauge reads overfull, stays that way for 200 miles, then begins to move and when it says half full tank I am out of gas. (Fuel gauge has been like this for a few years).
At first I thought it was fuel senders, but then I discovered that the miles-to-empty digital reading on the dashpod shows an accurate reading of my gas tank. So that points to the fuel gauge stepper motor which is a common failure mode.
I know how to solder so I'm going to try to install a new motor myself. Not sure if the motor is fixable so I'm going to just replace it.
I am a cheapskate and the cheapest one I could find was on Amazon for $25, here is the part:

https://www.amazon.com/Tanin-Electronix-TAE-Temperature-Stepper/dp/B01J6IBIP2/

This seller also sells on Ebay.
I will update the thread when the part comes in and when I have a chance to take the dashpod apart...


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