Testing so far hasn’t ruled out anything. The tests I recommended were simple, easy to do and required no disassembly. The next diagnostic steps will require some disassembly. When you grounded the sending unit wire you basically sent the signal that the sending unit would send with an empty tank. If the gauge didn’t go to empty, you have other issues. Could be a bad gauge, a bad ground inside the gauge cluster or faulty wiring, gauge or the wiring going to the gauge including the wire from the sending unit.
The first thing to do is recheck the wiring. Make sure you don’t have the wires switched on the gauge because it would destroy the gauge requiring replacement. I’m posting a picture of your wiring diagram in case you don’t have one.
I assume you corrected the power supply wiring to the gauge you initially said was coming from the ammeter. Check over the wiring and compare it to the diagram, then we’ll go from there.
Last edited by Phak1; 02/27/20212:04 AM.
Phil Moderator, The Engine Shop, Interiors and Project Journals
1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes Project Journals Stovebolt Gallery Forum
