fuel gauge issue

[boynton]

Ok so I have been chasing wiring gremlins in my truck for a while and have almost all of them worked out. One I need help with is my fuel gauge. As far as I know the only two wires that control your fuel gauge are the brown wire from the tank that runs from the tank to the fuse block and then to the gauge cluster and the other wire is a ground. I am thinking that my gauge harness may have an issue. Is there a way to wire strait from the tank to the gauge? I am using stock gauges. I tried this and the fuel gaige just went well past full and stayed there even when on empty. I thought that I may have a bad gauge, so I tried another gauge that I had that I know works and same result. Any ideas?

[TBONE1964]

Usually when you loose ground to the sending unit or the gauge it causes the gauge to read past full. When it is a power issue, it stays on empty.

You can run a wire right from the sender to the gauge. I would put a 10 amp in line fuse in the wire just to be safe. Make sure you have good ground on the sender and good ground on the gauge side. The ground on the gauge is the terminal towards the right when looking at the gauge cluster from the back side. It shares ground with the brake and temp warning lights.

You did not mention what your exact problem is. Does your gauge read past full or on empty? Maybe I misunderstand your post.

[boynton]

Originally Posted by TBONE1964

Usually when you loose ground to the sending unit or the gauge it causes the gauge to read past full. When it is a power issue, it stays on empty.

You can run a wire right from the sender to the gauge. I would put a 10 amp in line fuse in the wire just to be safe. Make sure you have good ground on the sender and good ground on the gauge side. The ground on the gauge is the terminal towards the right when looking at the gauge cluster from the back side. It shares ground with the brake and temp warning lights.

You did not mention what your exact problem is. Does your gauge read past full or on empty? Maybe I misunderstand your post.

Oh no you read it correctly and have answered my question perfectly. I think this is there exact information I need to get it going. Thank you. Ill try it tomorrow or Friday and report back.

[luvbowties]

Originally Posted by boynton

Ok so I have been chasing wiring gremlins in my truck for a while and have almost all of them worked out. One I need help with is my fuel gauge. As far as I know the only two wires that control your fuel gauge are the brown wire from the tank that runs from the tank to the fuse block and then to the gauge cluster and the other wire is a ground. I am thinking that my gauge harness may have an issue. Is there a way to wire strait from the tank to the gauge? I am using stock gauges. I tried this and the fuel gaige just went well past full and stayed there even when on empty. I thought that I may have a bad gauge, so I tried another gauge that I had that I know works and same result. Any ideas?

I also think you should double-check that part where it was said "the brown wire from the tank that runs from the tank to the fuse block and then to the gauge cluster and the other wire is a ground". You may find there is no hot wire going to the tank, but only additional grounding from gauge to tank.
Sam

[GMC Canuck]

An open circuit in the sensor circuit will cause the gauge to read way past full.
Take the wire off the sender and touch it to ground, this should make the gauge read empty. If you touch it to the tank, this will prove a good tank ground as well. If the gauge responds, problem is the tank sending unit, if not problem is wiring to the tank. You can ground the terminal where it comes out of the fuse block and that will isolate which part of the circuit you need to chase.

[boynton]

well it turns out it is the sending unit...there goes another $50 haha I was hoping just a little time and effort and maybe some extra wire would solve the issue

[GMC Canuck]

Thanks for the update. It's always good to hear the solution to the problem.

[boynton]

Originally Posted by GMC Canuck

Thanks for the update. It's always good to hear the solution to the problem.

Thanks for all of the help. It is simple things like this that I am unsure how to trouble shoot and great board members have continued to come to the rescue for me! Thank you to all of the wiser and more knowledgeable members that help out!

[TBONE1964]

Great, glad to hear you got it figured out.