Originally Posted by 1969 CON
I have a 1969 Chevelle. I put an LS2 engine in it and am using the front drive accessories for a Corvette (GMPP kit #19155067). I am also using the GMPP LS2 ECM and wiring kit (DBW) #19166568. I am trying to connect the alternator up. I have removed my old voltage regulator (BLUE, WHITE, BROWN & ORANGE wires) from the car. According to the wiring diagram for the car the BROWN wire goes to the GEN light inside the car. The wiring harness for the ECM has a plug marked "GEN" for generator that goes to the alternator. There is only one ORANGE wire in this plug. I've traced it back to the wiring harness' fuse box and it shows to be a constant 12V. When I purchased the front drive accessories I also bought an adapter plug for the alternator. This plug has four GRAY wires. Can anyone tell me how to hook up the alternator? Do I need to use the single wire from the ECM harness? Or, do I need to use the 4 wire adapter and wire it in? How do I wire this new alternator into the car's existing electrical system having removed the old voltage regulator? If anyone has a detailed diagram taht would sure help! I was trying to get this thing finished up this weekend. Thanks for your help!
If your new harness has just one wire, that's all the ECM requires to keep the alt. charging. That wire needs to go to pin "F" which is the second pin away from the engine,
and this will need to be a "key-on" 12V, not
fulltime battery voltage.
Sounds like your car has an idiot light. If want to keep it, you will need to wire the car harness's brown lamp wire to pin "L" which is the third one from the engine. That wire requires the resistance of the lamp to keep from frying the alternator.
Either of these two wires (independently)
will charge the alt., I'm not really sure if running them both together will hurt anything or not. My guess is you'll be OK with both...