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49 LS85 alternator wiring


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Can someone tell me the color codes for teh two small wires on the rear of the alternator. I took pictures but lost them when I changed out the phone. The three big leads are in order so I'm all set with them. This is not the gen set but the new for the time alternators with the big heat sink that hangs near the oil filter housing.

Any help is appreciated. I don't wan t to let the magic smoke out of anything I don't have to.



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I looked at my LS85 today and yes it has the 2 smaller wire on the top rear of the alternator , couldn't tell where they go cause they are in cloth wire loom, but I did look at my MACK wiring diagram and it appears that the small wire closest to the engine goes to the rectifier and is shown as a ground wire connection ,the outboard wire goes to the voltage regulator. to be sure I would use a continuity testor (flash light with 2 wires) and check to get a light from the wire to a ground point on the engine . hope this helps

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  • 10 years later...

@609albertwould you be able to share your wiring diagram? I have a 1950 LS and can't find any wiring information on the truck. I tried the Mack museum, but unfortunately they didn't have any information on my truck. The truck was rewired at some point but not correctly. The A-B switch and Amp gauges have been disconnected so the truck isn't charging and I am thinking this may be the problem but not sure.

I'm also looking for wiring on the ignition system as well.



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