[VetteVet]

Originally Posted by TA1754

Checked wiring on back of alternator, constant 12 v. there with key off.
Replaced my fuel gauge, put everything else back together, cranked the engine, amp gauge just stays in the middle, no matter if key is off, or engine running.
I paid somebody to rewire the entire truck over 20 yrs ago when the front clip was done.
Never really paid much attention to the amp gauge or the wiring until now.
Don't think it was ever wired correctly.
Trying decide if I should buy a replacement amp gauge, or find an auto electric specialist to help me out.
Don't think there should always be 12 v constant power @ each of the 2 terminals on back of the amp meter.

You will read 12 volts on each side of the gauge as long as the battery side wire is connected because the gauge terminals are connected together and they read the amperage that flows through it. You should see positive amperage when the alternator is charging and negative amperage with the key off and a draw on the battery, like turning on the headlights or starting the engine. If the gauge isn't reading either way then the circuit current must be bypassing it through another path.