Fuel gauge gone south!!

[jonnyquest]

Driving back from a 4 hour trip with a 6x12 trailer i just bought, the fuel gauge while at half a tank started moving back up to FULL??!!

I made it home, went to the fill up the tank, and with it full, the fuel gauge is rock bottom with the fuel light on.

Now the fuel gauge is on the bottom consistently w/ the light on.

Where do i start?

Thanks!!

Jonny

 

[Deep_palancar]

If you have a 99 or 00 you probably have a bad sending unit (it's in the tank) or a bad sending unit AND circuit card in the dash cluster.
The sending unit is not to too hard to replace. There is an access plate on the driver side rear floorboard.
Here is the TSB that lists the part # and the VINs for the suspect circuit board.

http://pages.sbcglobal.net/larsdennert/4runner/fuelsender/Instruments - Fuel Gauge Inaccurate.htm

 

[jonnyquest]

If you have a 99 or 00 you probably have a bad sending unit (it's in the tank) or a bad sending unit AND circuit card in the dash cluster.
The sending unit is not to too hard to replace. There is an access plate on the driver side rear floorboard.
Here is the TSB that lists the part # and the VINs for the suspect circuit board.

http://pages.sbcglobal.net/larsdennert/4runner/fuelsender/Instruments - Fuel Gauge Inaccurate.htm

Looking at that service bulletin, the #3 plate look very expensive and not easly to replace. I appreciate it! Can you elaborate a tad on the dash deal.

 

[Charlee78]

Hi, couple of months ago , a friend of mine had the same problem with his runner, we where able to fix it buy passing a new ground to the gauge. We did it at the sending unit, we spliced the ground wire (do NOT cut the ground) and put the other end of the wire on the body and Voila! Sorry but I am not sure if this wire is white and black. Let me know how it goes.

 

[Charlee78]

After that is fixed, you might want to check the wiring of your trailer, especially the ground. Make sure it dosen't take his ground from the tongue. Some trailers take their ground from the attachment, causing this problem in the runners.

 

[jonnyquest]

After that is fixed, you might want to check the wiring of your trailer, especially the ground. Make sure it dosen't take his ground from the tongue. Some trailers take their ground from the attachment, causing this problem in the runners.

Thanks Charlee, when we attached the trailer, there was a problem with the ground to the trailer hitch wiring. We grounded the adapter to the body of the truck. Not sure if this has something to do with it. It (the fuel gauge) worked fine after everything was attached, until we got just about home after a 4 hour drive.

I'm going to start by disconnecting everything we did to hooking up the trailer wiring.

 

[Charlee78]

I don't know why but runners don't like when we do this, my friend fryed his circuit board in the cluster that way.