Read lots of posts about wiring the LS1 4 pin CS-130 internal fan alternator into something else. I have a wire from my engine harness from PCM red 15 that says it goes to alternator and then I have another wire from the painless universal harness that says it goes to alternator excite. Which one should I use to excite the alternator and what should I do with the other? Is the one selected to go to the alternator pin B the wire that needs to go thru the idiot light?

 

Just use the wire from the PCM. If you want to be fancy, add another wire to the S terminal and run that to your main power distribution block.

Andrew