I recently removed my center dash cluster in my 1980 to replace burnt lights and clean. Before reinstalling every thing back into car, I bench tested all the gauges, because I had some cocerns about the temp gauge. I applied 12v from a 7ah cell battery and they all responed as they should. When I reinstalled the dash to the car, and run the engine the battery gauge doesn't work, it remains on 0 instead of reading between 12 and 14 volts. the rest of the gauges and clock work properly, as do the lamps. I have read recently that when bench testing the battery gauge, one should only flick or touch voltage to the terminal. I did not do this, I applied the voltage and the gauge read 12volts. Did I perhaps damage this gauge? Can anyone offer some advise?
ps the gauge was working before.

 

that would not dammage the gauge, you probably just have a bad connection on the back of the gauge

 

12 volts will damage an ammeter...not a voltmeter. It must be a wiring problem somewhere. [Note: The ammeter in early C3's is really a millivolt meter which is calibrated in "amps", but measures the voltage drop across a 'shunt' resistance which is part of the wiring harness.]