Bad gas gauge?

Red, I'm sure you know better than I. Can you actually measure the sender without unhooking the gauge?

Maybe the wire IS shorted, or the gauge already bad.

I always go underneath, unhook the sender wire, OR get into the kick panel, and access the rear harness connector.

Your sender wire in the kick panel connector is the dark blue, at one end of the connector. Here we are measuring mine, at about 24 ohms which should read --and indeed does --read 1/2 tank on the gauge. One wire of the meter is hooked to ground, the other meter lead is hooked to the dark blue in the rear harness connector