My ‘93 F150 has a charging issue and I can’t figure it out. I’m at the point where I feel like I need to rewire everything just to make sure I know there are no issues with the wiring.

If only mine was this clean

Here’s what I’ve done so far. It has a new alternator (which involved breaking other parts and buying a spare engine for said broken parts).


I took that new alternator back to the shop and had it bench tested just to be sure. It’s fine.

The battery seems fine, it shows 12.8V when disconnected and holds a charge and still starts the truck fine. I’m taking that in today to have it checked just to make sure though.

I checked the wiring and everything seems right at least according to this diagram of the wiring that I was able to find. Red and yellow both have power, there is continuity from plug to plug on white, and green shows a slightly higher resistance than 510 ohms but doesn’t seem excessive.


The only other thing I can think of is the plugs are somehow damaged and not making contact, but they look fine and even wiggling them around while the truck is running doesn’t get the alternator to work.

Am I missing something?