I have a 2004 LM7 5.3 with the current performance standalone fuse relay and I'm trying to figure out how to wire the 5.3 alternator into the my 85 chevy truck. I have a 3 wire plug in the c2 green connector pin 15 and 75. we dont have the GBCM we're trying to figure out if we need the 3 wires in the new harness or if we need any at all. How did you wire in the existing alternator wires from the truck harness, the red and brown from the existing plug.

Also I'm using the ac compressor off the 5.3, do I transfer the two R4 compressor wires to the new compressor? how is the AC request wired in?

 

Refer to my reply to your message. Have a PDF with some wiring, but too big to post, and dont know how to compress.