How do i get the gas guage to work? I guess ya'll have heard this one many times...I just keep a piece of cutoff water hose and stick it down there...I just wish that the guage would work!
Most of the time it is caused by a bad ground. Check the ground at the tank first.
If that is good you can check the resistances at the gauge -
S to Ground=68-72 ohms
S to I=19-21 ohms
S to A=19-21 ohms
I to A=Zero
I to Ground=49-51 ohms
A to Ground=49-51 ohms
If you can get to the top of your tank where the sending unit is located you can check your gauge by momentarily shorting the output wire (pink) to ground. It should show as full. If it doesn't move you have an open circuit or the gauge is bad.
Check the sending unit by measuring resistance between the round sender post (pink wire) and ground-
73 ohms=Empty
23 ohms=1/2 tank
10 ohms=Full
Also, you might have to drop the tank to get at the sending unit. Depending on how old your jeep is will dictate if you will have to replace the whole tank or not once you get it off. On mine, i had to replace the whole tank. Turned out to be a bad sending unit, so replacing the whole tank and sending unit solved a world of problems for me.