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Discussion Starter · #1 ·
I had to put a new timing chain and gears on my 1978 F-100, 302 CID. This truck is all original, including factory wiring. Of course, the first step was to disconnect the battery. When I removed the alternator I did not disconnect the wiring. I just set it aside and continued with the task at hand. Upon completion of reassembly I noticed that the two wires that have caps and slide on the studs on the back of the alternator had come loose. The main battery wire that is attached with a nut is still in place. I'm not sure which "studs" the other two wires go to. The truck runs great, but the "ALT" light stays on. I took the alternator down to AZ and had it tested. It tested good, but they swapped it out for a new one anyway under warranty. I also replaced the voltage regulator .... just because. One of the wires in question has a red cover at the connection that goes to the alternator with one wire and the other has a black cover with two wires. I have looked at numerous wiring diagrams and I am not very good at understanding them. I'm a pretty good "wrench" and can usually work my way through electrical problems. Charging system problems seem to always be difficult for me.

No, this wasn't a problem before I started this project.

I would really appreciate any help or even a picture to help me solve this. A simple and not too technical explanation or illustration would really help.

Thanks, in advance, for the replies.


1,971 Posts
if it were mine id stick a gm alt on it

very easy

got a 429 out back stuck in a 69 fairlane and its running on a gm alt

just connect wires to the battery and the one to the dash guage or light(the small wire)

the ford diagrams are odd to me also always

so many wires and complicated always

same with the ignition module boxes

fords pita

ill see if i can scan the diagrams i have or type out where they go by color for ya

time allowing anyways

so busy lately at the shop and other work and jobs never home

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