[Graham57a]

So late last night after a weekend of scratching my head and studying the wiring diagrams I finally figured out where my battery drain was coming from... I felt extremely dumb when I realized it but the previous owner had taken the pink wire (shown as purple/orange on the wiring schematic) from the engine bay harness that runs over the top of the firewall and ran it to the positive battery post on the starter. I didn't question the purpose when I put the truck back together but after studying the schematics I realized that specific wire was intended to SUPPLY power to the ignition coil and not receive power directly from the battery.

First I pulled both engine harnesses out from the truck, stripped all insulation and traced every inch of each wire. I thought somewhere in that mess I would find two wires that were welded together or something along those lines. While I did find a ton of crappy connections and bad wiring techniques, I did not find anything blatantly obvious. I took the opportunity to clean up everything, solder all connections, redo the ends, and heat shrink everything tight. So at the end I have basically a new engine bay harness and I still couldn't find my issue. I took a break and decided to study the schematic a little closer. You'll see in the picture below three wires shown leading to the starter solenoid, I was reading it such that the black from the battery and the purple from the ignition were tied to the same post. When I took a closer look and crawled under the Jimmy to see how that harness was ran I realized that was my issue. I disconnected the pink wire from the starter and bam, the drain went away.

I plan on using the pink wire to power my electric choke and then I have a pigtail soldered to the pink wire on the back of the ignition switch that I will use to power my HEI.

I had to finish off the night with a cold beer to celebrate my victory, it felt soooo freakin good to conquer that battle haha. Now I can bolt her back together and enjoy a few more weeks of decent weather before winter storage.