Wiring 4 pin alternator to 2 pin harness?
 

Im working on a green/blue harness from a '05 or '06 truck with the 2 pin alternator plug and I need to know what I have to do to the harness to use the 4 pin alternator thats on the motor I already have ('03 5.3). So I need to know other than getting the correct 4 pin connector what wire(s) need to go where to get everything to work correctly with this newer harness?

I think you will have to switch out the regulator to a 2 pin if you want to go that route. Now you could buy a 4 pin alternator harness and plug it
into the alternator and wire it up. Then leave the 2 pin harness alone and off to the side taped up.

Well I already have the harness completely apart to rewire, relocate and lengthen it so wiring in a 4 pin plug is no big deal, but I need to know where to wire it to. The '05-'06 harness Im using had the GBCM originally which is where the 2 wires from the alt went to, not to the pcm like my other car that I swapped a '00 4.8 in. The '00 harness only has 1 wire coming off the alt and going to pin 15 on the red connector of the pcm, Im trying to figure out where I have to run the wire(s) from the 4 pin alt to on the new (green/blue) pcm.

Anyone?

Here is what I did when I went from a 2 wire to a 4 wire. Post 542 starts to cover it and goes on for a few posts.

https://ls1tech.com/forums/conversio...0-swap-28.html

Went through the same process with my harness. It is better to wire the 4 pin alternator just as 1989GTA does in his posts. When I tried to wire the 2 pin it just defaulted the output to 13.8v and dropped much lower with everything running. The 4 pin can be wired to sense the voltage and provide more output if needed.

That was my experience as well.

I have a brand new DR44G 2-pin alternator I am looking to get rid of cheap. PM me if interested.

Ok looking at this wiring diagram it looks like that pins b & c on the alternator go to pins 15 & 75 on the green pcm connector from the factory, so Im gonna wire it up that way and see how it goes.

https://repairguide.autozone.com/zne...3f802412ad.gif

If you go to this site about half way down, they tell you exactly how to hook it up depending on which style 4 pin alternator you have. It is relatively easy. You need one wire to turn the regulator on/off, and one to detect load if you want to hook the load wire up. The GMPP harness only has 1 wire to turn the regulator on/off.

http://www.pirate4x4.com/tech/billavista/Wiring/Part2/

A number of the truck alternators are self exciting and don't even require a signal from the PCM if you wish to go that route.

http://www.norotors.com/index.php?topic=6897.0

Just an option but you'll need another alternator.