love2fixit,
I guess I must have OCD...I need to find the reason for this gremlin.
I drew a little cartoon, and if I understand all I think I know about the fuel gauge, which might be a stretch, it almost looks like the wire from gauge to sender or the sender to ground path might have a high resistance connection in it somewhere.
When you pull the gauge from the dash assembly, its ONLY path to ground is through the sender. This is a tough path, but it's the only path.
When you stick the gauge back into the dash assembly, the gauge case now has a much easier path to ground, which is saying it sees the connection to the sending unit as a OPEN and it goes to FULL.
The connection to the sending unit on your truck is made on a common terminal in the fuse box. Could this connection be full of fungus or almost ready to fall off?
I don't know if this theory is right or I need more meds...someone will show up and set me straight!
Stuart
