Amp gauge works backwards!

[HSRACER]

My factory dash 69 was completely reworked by the previous owner. The amp gauge shows discharge while driving down the road. I put my volt meter on while idling and shows 13.5 volts while the gauge is showing discharge.

Is it possible the gauge could have been wired backwards somehow? I know the plug into the stock dash is still in place to power the cluster so I wold like to know the gauge wiring so I can check proper continuity.

Any help is appreciated! Thanks
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[VetteVet]

Your gauge plug wiring should look like this.



The two wires at 1 and 12 are the gauge wires and they originate in the engine compartment. shown here.



The first diagram shows the wires as both being black with a brown stripe and the second show them as being a solid black and a black with white stripe. You may have something similar or different,

Turn the key on without starting the engine and watch the gauge while you turn on the lights and step on the brakes. The gauge should move to the left
showing discharge. When you start the engine the gauge should move to the right showing charge. If it works the opposite then chances are the 1 and 12 wires are reversed in the gauge plug. These wires are both positive so use care if you switch them. The fuses shown are 4 amp fuses to protect the gauge from overvoltage. They are inside little football shaped rubber housings
located by the battery junction on the right passenger fender and by the voltage regulator on the left side of the radiator.

The dash cluster is wired as shown and the wires at 1 and 12 are shown going to the ammeter.

[HSRACER]

Thanks. This truck has an aftermarket wiring harness and the factory fuses are all gone. The diagram you provided will be very beneficial as I check voltages. So do you see any issues with just switching terminal one and twelve?
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[68gmsee]

Originally Posted by HSRACER

Thanks. This truck has an aftermarket wiring harness and the factory fuses are all gone. The diagram you provided will be very beneficial as I check voltages. So do you see any issues with just switching terminal one and twelve?
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Shouldn't have issues. Amps are read in series to a 12 volt supply so switching the wires won't hurt the amp gauge and probably will fix your problem.