62 c20 generator to alternator help needed
 

Trying to figure this out. I know it's not that complicated but I'm missing something. Everything I've read says take the brown wire for the generator light running from the firewall to the voltage regulator and run it to the #1 terminal on the alternator per the diagram below. I have a brown wire from my generator to regulator but I don't have a brown wire coming from my firewall...is a 62 color scheme different? Just trying to find the right wire for my gen light. The harness from my firewall has dark green (horn), a light green and a tan (headlight) and a large gauge red and smaller gauge red which both run to the same terminal on the voltage regulator. Can anybody help a wiring dummy out?

Re: 62 c20 generator to alternator help needed
 

Yes, the early 60's do have some different colored wiring as compared to the mid 60's & later.

The wire for your "GEN" light is that smaller gauge red one that runs from the "A" or "ARM" terminal (middle terminal) on the old voltage regulator to the firewall connector. It should be sharing the "A" terminal with the brown wire that goes to the generator. It's this smaller gauge red wire from the firewall that you'll want to re-route to the #1 terminal of an SI-series internally regulated alternator.

The heavier gauge red wire that runs from the old voltage regulator to the firewall connector is the main power feed wire into the cab. It originally connected to the "B" or "BAT" terminal on the old regulator. And this "B" terminal would also have a red wire running to the horn relay along with another wire running over to the positive battery terminal. When you eliminate the old voltage regulator you'll want to install some sort of buss bar or junction block/stud that can serve as a main power distribution point where all these wires can stay connected together. The output wire and voltage sensing wire (#2 terminal) from your new alternator should also be connected to this main power distribution point. Note: This main power distribution point I'm describing is represented by the large "dot" where all the 12R wires connect together on the diagrams you posted.

Re: 62 c20 generator to alternator help needed
 

Thanks so much ray, you are the man!