alt wiring

[grizwald]

this is more a question out of curiosity, but i've switched to a one wire alt, and no longer need the factory plug. so, i was taking it out last night and trying to eliminate the wiring altogether. i noticed that the brown wire (which i thought was hook to my volt guage, but isn't) has 12.5 volts with the key turned to ignition. just wondering why? i'm sure this is a dumb question...but i like to learn :lol:

 

[Doober]

That's what turns the alternator on. The circuit goes something like this:
battery - fuse block - ignition switch - "charge" bulb (in the dash, same as the 'battery' bulb) - brown wire that goes to the alternator. The wire that goes to this plug on either a CS or SI alternator both do the same thing... the 10 gauge red wire on the SI alternators are to aid in regulating voltage properly, but some guys just tie it to the post on the back of the alternator. For your voltmeter I would just tie it in with the power to the rest of the gauges... or is this gauge somewhere else?

 

[grizwald]

the guage is wired directly to the fuse panel. i didn't realize that anything supplied power to the alt. so i was kind of surprised. i'm not re-using any of the wiring, just curious. it's all starting to make sense to me now, i think. one wire alt=self energizing....meaning it doesn't need that 12V supply to turn on. i HATE having to cut wires and tape them off...but i can't see tearing the wire harness apart to remove that wire completely. guess i'll save it as an extra ignition source should i ever need it.

thanks doober!

 

[Doober]

Don't use it as an ignition source. Power goes through the bulb, so anything you supply to it would be getting less than 12v, plus the light would possibly turn on, leaving you scratching your head. Only way I can think of for ignition-switched power in a G-Body is running a new wire and running whatever you're hooking up off a relay, there isn't really anything outside the coil that is powered by the ignition switch directly.

 

[grizwald]

true...never thought of that. guess i'll just get rid of it then.