Fuel gauge or sending unit?

[superc_1]

What the easiest way to find out if its the fuel gauge thats bad or the sending unit in the gas tank. I think I read somewhere that sometimes the contacts just need filed?

[datzenmike]

Ground the Yellow wire that goes to the sender on the tank and the gage should read full with key on. If not, check that the Black wire goes to ground. It connects to the tail light ground wire. As for contacts being filed... there is a small voltage regulator in the instrument cluster, but it also works the temp gage, so if the temp gage is working, it's working too and is fine. Because the tank is exposed to all road conditions a wire has probably rotted off from corrosion.