Electrical Alternator not charging after terminator 2 install.

Sfab79

New Member
Aug 24, 2025
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Kamloops,bc
Hello all, I did a terminator 2 install on my 91 Fox, and since then my alternator is not charging and no charge light on the dash, I have 130 amp 3G alternator, installed, new PA performance 3G regulator and brushes, I know the charge light is not burnt out because I unplugged the cluster put it on The bench Used direct power to the two wires that go to the amp light. I have power also at the ignition switch, I did replace the ignition switch just to be safe and not be stranded, any help or ideas from anyone would be amazing.
 
Obviously at 12.0 to 12.5V+ it’s not charging. It is in the alternator wiring. I would trace the ignition wire from the dash (after the alternator light in the dash and make sure that is getting to the alternator.

This is a post on how the 3G is supposed to be wire and some common things that cause it to not charge:

Post in thread '3g Alternator Green Wire Trouble'
https://stangnet.com/mustang-forums/threads/3g-alternator-green-wire-trouble.896195/post-9031908

I know that there are two dash harness connectors behind the driver shock tower on a 91. I’m pretty sure both of these connect to the ECU harness but am pretty sure they have nothing to do with the alternator. The alternator wiring is part of the headlight harness.

The headlight harnesses are year specific. Yours is 91-93.
 
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Great info, much appreciated! Yeah, I totally feel you, I just threw another alternator in it today brand new, not rebuilt and still the same thing, and it is just extremely strange to me that it worked flawlessly a month ago before I did my terminator swap, It’s definitely left me extremely puzzled because the Terminator is on a totally different system
 
Yes fair enough, just very very strange everything was fine before T X install

You may be the only participant in the thread that thinks that this is odd.

I mean, [lots] of things can happen to wire harnesses and connectors with power plant swaps. :shrug:

I would imagine that you swapped in the harness that goes with the engine and ECU? So, this harness would be new to the car?

I don't find it strange at all that there could be some wiring gremlins in a project like this. I'd be blown away if there were [no] issues. O_o
 
1000%! I don’t disagree. I just find it strange and weird because I have 6 foxes and four now have the Terminator swap and this is the only one I’ve had trouble with and I’ve done many to my friends vehicles also.