chevyagain66,
When you did the test Wrenchbender outlined, did you perform it at the sending unit on the tank? If you did, and it proved the gauge and wiring good as you indicated, then it would seem that the problem is the sending unit.
When you attach the wire to the sending unit and turn the key ON, the gauge goes to full EMPTY, right. This would indicate to me the sending unit is shorted somewhere.
I think this rig has a connection point for the wire from the gauge, and the wire from the sender located in the fuse block. It isn't a fused connection, just a connection point. If your test proved the wire and gauge good, the problem should be the sender, or maybe some problem with the connection at the top of the sending unit.
PS. If this has NEVER worked since you installed it, don't discount the fact it might be stuck or the float has sunk, and it is indicating what it perceives as a EMPTY tank.
Stuart
Last edited by atomarc; 12/09/2007 6:15 PM.