Chances are there are no wires on the back of the gauge. Connections are made by an overlay. How full does it read? My sending unit went bad one time and the gauge went so far to full side that I couldn't even see the needle. New sending unit and all was better. There is a ground wire that runs from the sending unit to the frame that sometimes gets coroded and loses contact. If you get under and look up, pass side front of the gas tank near the corner, you sould see it.
Yep, All I got for trying to find the wires under the dash was a bloody hand.
The gauge reads the same as it would if the tank were full of gas, but since I did not fill it full to create this event I doubt it is a stuck float.
I guess dropping the gas tank is in order, because I can not access the sending unit from underneath, I can get my hand up in there and the connections feel fine, but in order to replace the sending unit, or even inspect it, the tank must come out.
The sending unit seems to be in the center, front, top of the tank.
EDIT: Thanks for posting the proceedure, that should help a great deal.
