57 Chevy with an Autometer traditional chrome fuel gauge. Works well until I turn the headlights on, then the fuel gauge drops to near zero. Turn the headlights off, gauge returns to correct reading. I have replaced the fuel tank sender just to eliminate that possibility (gauge acted this same with either tank sender). I have now removed the gauge cluster to grease the speedo cable and to try to trouble shoot this fuel gauge issue. I read the voltage on the voltage input wire to the gauge and with the engine running reads 14 volts. Then I turned on the headlights and the voltage dropped to 13.4 volts. Turned the headlights off, voltage went back to 14 volts. Talked to Autometer tech but did not get any help there. I asked if it could be a problem in the gauge itself and did not get a straight answer from Autometer tech. I have a Power Master high-output alternator on the car. Any help will be appreciated. Thanks, Larry
Update: I tested the gauge alone with the dash cluster out and it now works as it should. I don't know why it didn't work when is the dash cluster but so far problem solved.
Update: I tested the gauge alone with the dash cluster out and it now works as it should. I don't know why it didn't work when is the dash cluster but so far problem solved.