[67farmtruck]

Got it figured out - kudos to all of you guys for helping me learn about my truck's ignition system, and especially LockDoc and ray_mcavoy for helping me think simple when things seemed most complex.

ray_mcavoy made a great observation that I had only checked for +12V at my red ignition wire with the key off. With the key in "run", voltage dropped to +1. Thus, I needed to find the source of voltage drop between battery and ignition.

I recently put a new battery in this truck, so I started with the battery connections. Fusible link looked suspect (couple frayed wires - maybe that's the source of the voltage drop - might have broken when I took the + cable off?). So I replaced that with a piece of straight 12ga wire, but it still wouldn't crank. Then I noticed the negative terminal on the battery was a little loose, so I took off the cable, cleaned both ends and the engine block, hooked it back up real tight and boom - away she went firing on all cylinders!

Lesson learned to always think simple and check your work - great teaching point for my son who wants to drive this truck to prom this weekend.

Thanks to all those who chimed in and helped me learn about this truck's ignition system. Although I replaced a lot of parts I didn't need to, they were cheap and it's money well spent to get my hands dirty on a truck I love. On to the next challenge - brake pedal that goes to the floor!