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Alternator wiring help!

  • Thread starter Thread starter ty50650
  • Start date Start date Apr 28, 2025
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ty50650

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Apr 28, 2025
#1
  • Apr 28, 2025
  • #1
Hello, I have a 1990 Mustang 5.0 that had a bad alternator. I originally bought a replacement from oreillys which had the rectifier plug connected to the new one with 3 wires coming out to crimp connect to the harness. I had cut off the alternator connector from my mustang (shouldn’t have) and was going to crimp together but decided to order an oem replacement from LMR instead that would connect directly to the replacement alternator. Now I have a new plug that I am trying to connect and am wondering how to tell which orange and black wires connect to which. I should have labeled them but did not. I’ve attached pictures for better clarification.

If anyone could let me know how I could determine which wire goes to which, it would be greatly appreciated. Thanks for your help!
 

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Noobz347

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Apr 28, 2025
#2
  • Apr 28, 2025
  • #2
It doesn't matter, they both go to the same place.

I would solder those connections vs. using barrel connectors.

You [could] also, cap those wires and tuck them out of the way. Run a a new [fused] 4 gauge wire from the alternator to the [Hot] post of the start solenoid.

Refer to this post for a bit more clarification: https://stangnet.com/mustang-forums/threads/3g-alternator-install-a-how-to.646825/#post-6673702
 
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