Author Topic: GM 3 wire Alternator in an 81  (Read 1791 times)

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oleblue22

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GM 3 wire Alternator in an 81
« on: Nov 13, 2016, 12:27:20 PM »
I've searched for hours and can't find anything on the wiring of it. I'll be running a winch and LED light on roof. I'm thinking that along with running heater and headlights at night is gonna be more than the 40 amp stocker alternator can handle. I have the motor out now so I want to do this swap while it's easy to get to. I was going to get the trail gear bracket kit for the swap and one of the alternators they recommend on the site. There are alot of threads for the newer trucks with the internal regulator but mine has the external regulator mounted on the driver fender. I wouldn't mind going with the 1 wire due to simplicity, but my truck has a factory volt meter and I'd like it to work and really don't want to deal with the charge light being on all the time. If I can get the volt meter to work with the 1 wire GM I'd use it but from what I have found so far, sounds like the three wire will be needed for that. I have the 5 wire external voltage regulator on mine and the three wire plug on the back of my alternator with a green, yellow, and white with black stripe.I have found many folks asking for the same thing but mostly dead end threads. Has anyone did this swap and can help with what wire goes where? I have pictures of my alternator plug and voltage regulator wires but can't figure how to put them on here.  I appreciate any help.

OOPS

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Re: GM 3 wire Alternator in an 81
« Reply #1 on: Nov 14, 2016, 06:08:37 AM »
David & Theresa Fritzsche, 1990 Ex-Cab with a few mods!!!!!!!!! Roseville, CA Sobriety =Serenity

mudmaster

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Re: GM 3 wire Alternator in an 81
« Reply #2 on: Nov 14, 2016, 07:20:31 AM »
This is what I did also.
Time to go wheelin!

oleblue22 [OP]

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Re: GM 3 wire Alternator in an 81
« Reply #3 on: Nov 16, 2016, 05:15:46 AM »
I understand the schematic but on mine, I have more and different color wires than what that diagram is showing. Did you guys have the external regulator? I have the 40 amp three wire plug alternator with external regulator. Did you unplug the regulator and wire off of those wires or the wires going to the alternator? I have a green, yellow and white with black stripe on my alternator plug. On the plug that goes into the external regulator, I have two yellows, a red, a green, and a white with black stripe. I'm assuming tie the two yellows together, and use the red but what would be the wire for the "S" sense wire, the white with black stripe or the green?

OOPS

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Re: GM 3 wire Alternator in an 81
« Reply #4 on: Nov 16, 2016, 06:03:24 AM »
Mine is a 90 and did not have an external regulator. Do not know how to do yours.
David & Theresa Fritzsche, 1990 Ex-Cab with a few mods!!!!!!!!! Roseville, CA Sobriety =Serenity

mudmaster

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Re: GM 3 wire Alternator in an 81
« Reply #5 on: Nov 16, 2016, 06:34:30 AM »
Time to go wheelin!

 
 
 
 
 

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