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

 

http://oljeep.com/gw/alt/Alternator_Theory.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.

 

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.