No power to cab

[nail pounder]

Before I start chasing my tail I figured I'd ask. Went to move the 66 today so I could work on the Apache, started fine a couple times, then went to park it in the driveway and I have no power. No headlights, doesn't crank, nothing. My temp and gas gauge seemed to work. Any thoughts on where to start? Battery is good, connections seem fine. Haven't​ had any issues for years.

['63GENIII]

Pretty sure that power comes to the cab from one of the terminations on the horn relay. You might also have a bad ground as well. Funny that I ran across this thread. Just within the last 2 days on the way to and from work, Ive hit the same group of potholes on the freeway. Both days, when I hit them, I lose almost all power to the truck. Dash lights, head lights, the engine cuts out for a split second and then just like that, everything is back on. I thought about it all day at work today and realized that I had removed all of the body to frame grounds during the rebuild. I guessed that when I hit the bumps, whatever was grounding the body was losing contact. A little experiment followed. I made a jumper out of a couple of alligator clips and some #10 wire. Before I drove home today, I clipped one end to my main engine ground and one to a stud on the firewall. I hit the same potholes on the way home today and it didn't skip a beat.

Moral of the story, check all your ground and if you don't have any extra ones from the body to the frame, that could be a part of the problem.

I know what Im doing this weekend.

[nail pounder]

Good call, I'll start there. Seems funny that the temp and fuel gauge still worked. It's probably an easy fix I just need to look into it. I've neglected it a bit, been too busy driving the wheels off it and working on the Apache, probably time to tune it up too & maybe swap to an HEI dist.

[nail pounder]

I didn't have much time to fool around with it today but here's what I found. Grounds look good, I have 12v to the fuse block UNTIL I turn the key on, then I have 2-3v. So I think I need to see what's going on at the starter. Maybe the solenoid? I drove a 79 Scout for 14yrs between high school and after, it had a similar issue and I used to turn the key on, crawl under and jump the solenoid with a pair of channel locks. Being young and broke I just hooked up a toggle switch, ran some wires and drove it like that until I sold it. Any opinions?

[AcampoDave]

Also check the bulkhead connections where the harnesses from the engine compartment plug into the cab. And as mentioned the hot lead from the horn relay. Before reaching the relay, it originates at the battery.

[Cooper197]

My buddy ran into this exact same thing on his 73 a few months ago. It was the starter solenoid.

[nail pounder]

After work I micky moused around with a volt meter and test light, 12v everywhere except when the key is on, hmm (thinking). Tried jumping the solenoid, got nothing. Double checked grounds, bulkhead connection, fuse box, etc for an hour or so, all look good. Started wondering if my battery was smoked but somehow still reading 12.5v, it is 5yrs old and I've heard of that but never experienced it, hmm, did some head scratching. I put my battery charger on it and low and behold dash lights up everything seems to work...Hmm. I turned on the head lights and removed the charger hot lead and everything turned off, re-attach and everything turns on...Hmm, more head scratching. Got a ½" wrench and some sand paper, pulled the battery hot lead, cleaned it up and I'll be darned it fired right up. Basic mechanics 101, check the simple stuff first. Son of beach, I'm an idiot.

[The Rocknrod]

Well your not an idiot by any means, I mean who'd a thunk?