my gauge hasnt worked since i bought the car, its pegged. i want to make sure its the sending unit before it just replace it. if i unplug it, it should drop to 0. and if i take a jumper wire or paper clip and connect it to the two wires, it should go all the way up right? i did that but it stayed pegged when i unplugged it. any ideas?

I replaced my sender recently that was acting similarly. I did not try diagnosing the circuity at that time- jsut screwed in the new sender and turned the key- worked fine.

You might try buying a new sender and plugging it in before you physically install it in the block- just dangling in the air. If it doesn't read zero on the gague like that, you have wiring or gague problems.

I'm not sure jsut unplugging it is a valid zero-test. I know my gague will just sit where it feels like it with the key off. As soon as I turn the key on it will go to zero before starting it. I'll bet the circuitry needs current flowing through it even to zero-out the gague.

im a bit short on cash at the moment and ive done enough of the just replacing parts, hoping it will fix it. ive learned i should actually diagnose stuff first. any way to do it to verify the gauge and wiring is good?