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Discussion Starter #1
Working on adding an SS dash with gauges to a 71 Chevelle. Finally got everything working however, when I increase the RPM the AMP gauge is indicating a negative charge and when I turn on the headlights I get a positive charge. As the gauge appears to be installed correctly the only thing I can think of that would be causing this strange condition is the single wire alternator that I am using. Has anyone had a similar experience?
 

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Is the alternator output, the one wire, attached to the battery or the horn relay? The factory wiring has the alternator output going to the horn relay, making it possible for the amp gauge is to measure the current flowing into the battery, charging, or flowing out of the battery, discharging.

With the engine off and the headlights on what does the amp gauge indicate?
 

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Discussion Starter #3
With key in off position and headlights on I get movement to the positive side on the amp gauge. As I am using factory wiring I suspect the connection is to the horn relay. Do I have it wired backwards to the horn relay ?
 

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If the gauge is indicating charge when the lights are on w/engine off. I would say the gauge is wired backwards.
 

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Discussion Starter #5
Elree, as it is assemblied into a unit and powered by a printed wiring board I think this is going to be more difficult than I thought. Could it be manufacturing defect in the gauge?
 

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See this post. I was thinking you added the wiring for the amp gauge. Did you get original or reproduction dash and forward lamp harnesses?

If it is all original and the alternator output is wired using the original wire, then it's unlikely that it is wired backwards. However with the ignition off and the headlights on the amp gauge should indicate discharge, if it indicates charge the gauge is wired backward.

The wires can be switched at the cluster connector without too much trouble.
 

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Discussion Starter #7
OK sounds like a plan, let me geve the wire switch a try and see if that corrects the problem. Thanks for the help
 

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Discussion Starter #8
That did indeed fix the problem. I switched the wires at the console plug and the gauge now indicates correct reading. Not sure why using the correct wiring harnesses the wires required changing but stranger thing have happened. Thanks for the tip on resolving this problem.
 
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