# Alternator Wiring



## hayes68gto (Jun 19, 2012)

This may be a stupid question, but the car was in pieces when I bought the car. I put on a new alternator. The existing wiring has 2 connectors, but nothing to the ground terminal. When I start the car, the generator light stays on. I wondered if I have to ground the alternator and if so...what is the best place? Any advice?


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## BearGFR (Aug 25, 2008)

The alternator ought to ground just fine through its housing to the brackets to the block.. etc.

First things first. Find out if the light is lying to you. Get yourself an inexpensive digital multimeter if you don't already have one. Start the car, measure dc voltage at the battery terminals. If you've got 14.4 volts (or very close) then you know your alternator is charging and the light is lying to you. If you DON'T have at least 14 volts, then highly suspect you've got a bad alternator - take it up to your local big box parts store and have it tested. The circuit that turns the light on is in the voltage regulator, so the problem could be there. Also, check all your fuses, especially the one that goes to "accessories". On my 69, if that fuse blows all the gauges and everything will still work, but the alternator light will come on because with that fuse gone the power that comes off the alternator that's normally used to turn the light off will instead "back feed" through the panel and operate the gauges and lights but the feed from "the other side" that turns the light off can't get there (due to the blown fuse) so the light comes on. Figuring that one out was a real head-scratcher.

Bear.


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