Ok... Putting my dash back together and testing things one by one as I put them in. I put my gas guage in and hooked it up. I turned the key and it(The gauge needle) swung to the 3 o clock position. I have an Oldsmobile factory service manual and with the testing procedures I can do, I figured it was either a bad ground at the tank, or the gauge was bad. I cleaned the ground to the body crossmember and checked the power to the sending unit. My test light came on so I guess that's ok. The gauge still reads at 3 o clock. So... I tried another gauge. Same result. The factory service manual really doesn't go much more than that except for having some probably obsolete factory testing tool. Any ideas?

 

Did it work before you redid the dash?

Do any of the idiot lights work? If so, then try this:
Find the tan gas gauge wire within the rear body connector in the trunk area. Short it to ground and the gauge should move to empty. If this happens, your gas tank sender unit is bad or the wiring near it is open.

 

Yes the gauge worked before. I guess I will try to short the tan wire to ground.I checked and there is power to it. I was afraid to short it so I put a test light to it. I suppose... I will have to put a sending unit in. I will be sure to fill it up with gas first. lol

 

Yup. Sending unit is junk.