fuel gauge?

[69GS]

My gauge is stuck on full. Been told this is the sending unit, or the ground wire. The wire to the chassis looks good and solid (not rusted). Year 1 wants $150 for a new sending unit, before I waste the money and the labor, anyone have suggestions?

[MikeM]

Mine got stuck too for a little while. I think it was due to lack of use. Drive the car on some bumpy roads, that may shake it loose. Sounds stupid, but mine came loose after driving the car around for maybe a 100 miles or so. You might also try banging on the tank where the sending unit is with a hammer. Some of the more expert people may know which size hammer would work the best.

[72staged]

You can buy them at the auto parts store for about $50. I can give you a part number if needed.

[69GS]

Really? The Year One part is GM remanufactued, but if the aftermarket works, I'll try it. What's the part number?

[mltdwn12]

Ed go to Rockauto.com and go through their catalog, only took a few seconds to get to the sending unit for your car and they show two, a standard unit for $39 and a premium for $50

[doc]

With the fuel gage, it works by grounding it. Disconnect the wire back at the tank sending unit and see if the gage goes to zero. If it does then ground the wire to the frame some where and see it it goes back to full. If it does then the gage and the wire are OK.
the tank sending unit needs to be replaced.
If the gage doesnt change from full when the wire is disconnected then the gage its self is defective or the wire is grounded between the dash panel and the tank sending unit somewhere.

[69GS]

Thanks for the info doc. Finally got the time to thoroughly run these tests, here are the results: When I disconnect the wire from the unit back it stays on Full. Only when I connected a jumper wire from that connection to the chassis does the needle move toward 0. Which may be the actual reading (because I've been adding only small amounts of fuel in anticipation of dropping the tank) So do you think the wire from the unit to this connection isn't grounded and/or the unit is still bad?
I also disconnected the ground wire and it also stayed Full. :Do No:

[doc]

Ed,
When you ground the wire that connects to the center terminal back at the tank, it should bring the gage to the ''full'' mark completely. If it doesnt then the gage or the wire is defective. If it does move to full then the gage and the wires are good and the tank unit is defective.