I have an '86 IROC that isn't charging. I've got battery voltage at the red and black wires in the plug at the alternator but I'm not reading anything on the brown wire (all with the key on engine off). When i start the car I get batt voltage only at the output post of the generator. I had the alternator bench tested by advance auto parts and they said it was ok (normally I wouldn't believe them, but without power at the brown wire I gave them the benefit of the doubt). I've already checked all my fuses, all were good. Where should I go from here? Also... could I use a paper clip to jump the black and brown wires on the alternator? I've read something about a resistor in line on the brown wire... how much trouble could I get in by doing this?

 

You won't damage anything using a paper clip even if there was a resistor wire originally. If you want to make absolutely sure nothing blows up, you can use a brake/ turn/ main lamp instead of the paper clip. That'll limit the current to safe levels even if there's a short in the generator.

 

Well.... here's my outcome. I rechecked all the wiring today. Turns out I had power on the wire that's supposed to have the resistor (brown wire), I had power on the thicker batt wire (black/red one in the plug), but no power on the black wire. So i started tracing the black wire. Turns out it was never hooked to anything. So I jumped battery power to that wire and started the car. The alternator was still not charging. Replaced the alterntor and now it works like a champ! Got 14.2 at the back of the alternator and 13.8 at the batteries (They had gotten run down during the whole process). Anyone have any idea why GM would incorporate and unneccessary wire or what that wire might do?

 

where did the black wire go to