my gas gague does the following: i switch the car on and the which is needle is sitting on full, goes slowly down to the third letter in temperature-way past full.
can i assume the gague is working or not ? i have undone and rehooked the tank ground wire with no difference.
how hard is it to replace a gas gague in a 69 chevelle if necessary ?
could i do an aftermarket gague some place instead ?
my tank though undercoated does not leak, a new sending unit and new remote gague a possibility ?
thanks.

The gas gauge circuit is open somewhere. First you need to test the gauge circuit to make sure its working correctly. Go into trunk and unplug the connector for the rear harness. Its here.

http://www.chevelles.com/showroom/data/500/Dsc00888.jpg

With the connector unplugged and the key on, gauge should peg to "F". Next you need to ground the light tan wire with a piece of test wire, a inline fuse (10amp) for safety, and some alligator clips. Heres a pic

http://www.chevelles.com/showroom/data/500/Dsc00889.jpg

Using the tab for the 18g tan wire inside the connector that goes towards the front or the car you are simply making that wire go to the body of the car. Make sure it goes to a clean BARE METAL spot to get a good connection.
Heres a pic

http://www.chevelles.com/showroom/data/500/Dsc00890.jpg

Do this with the key in the on position. The gauge should peg to "E". If it does then the gauge is working correctly and the problem is at the sending unit or the ground for the sending unit. Check the ground at the tank, make sure it goes to clean bare metal.

Thanks, I appreciate your taking time to help.

If you have any other questions or problems, post or PM.