Alternator Connector Plug

Mark Setter

Silver Supporter
Can anyone tell me what plug I need to attach to a GM Alternator #25766345 that is normally from a CTS-V 2005 5.7L? I want to wire the alternator and I am having trouble identifying which plug will fit this alternator for a three wire set up.
I believe it's this one. This plug was used on the LS1 Camaro, C5/C6 Corvettes and early CTS V. The GMPP harness only uses the one wire from the C3 connector at the ECM "position 7". That wires enters the alternator connector at position "B". The wire in the plug connects to the terminal marked "L" on the alternator.

Alternator (Generator) Connector Pigtail for LS1 Camaro Firebird - EFI Connection, LLC

In the link I gave Mark you can see the cross reference numbers to Auto Parts Stores equivalent connectors.
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Mark Setter

Silver Supporter
Wow Ken, thanks for your help. I will order it now. A while back you gave me a suggestion on increasing the diameter of my air intake. I took it seriously and I am looking forward to showing you what I have come up with. I appreciate your help.
You can probably go to your nearest auto parts store and find it on the shelf. They were used in trucks as well. You will only be using the wire marked "B' though. Print the picture out and take it with you to help identify it.

I hope others will step in to confirm this.

Mark Setter

Silver Supporter
Hi Alex:

Thanks for this information. Up to this point, I have used Holley stuff where ever possible, so following your suggestion I have this harness on it's way. Having the additional wiring and resistor built in is certainly an advantage.

I have appreciated all of your input throughout this build.

Mark Setter

Silver Supporter
I purchased the Holley Alternator Plug. Looks and fits great. The question is, "There is one wire coming out of the Holley Plug. What or where do I attach this wire to?"

Will Campbell

Bronze Supporter
Mark, be sure your alternator needs a simple 12V signal. Most don't and sending them a 12V signal on the exciter terminal (usually "L") may damage it.

That's why the GMPP harness has a resistor inline- so the voltage is reduced.

Mark Setter

Silver Supporter
Thanks for the info Will. The Holley cable I am using does have an in line resistor, so I think I am OK. Please tell me if I am wrong.

I have said it before, but it needs saying again. I am sincere in saying "Thank You" to the experienced builders for keeping an eye on us beginners, keeping us out of trouble and helping us along our building journey.