The Stovebolt Site Forums The Shop Area The Electrical Bay 1949 GMC 1 Ton electrical wiring??

Ok, so I've finally got another AD. Only been about 12 yrs now since I've had one and probably just as long since I really posted on this site.

Funny enough my very first truck which was a '50 Chevy 3/4T is now for sale except it's way over priced so I just picked this truck up for $1000. 1949 GMC 1 Ton with PTO driven dump box which supposedly works. Probably going to start selling various pieces from it like the delux heater, hubcaps etc as I wont be using some parts for my project. Was a previously running/driving truck which I plan on making a daily driver ASAP. Then it's going on a '76 motorhome dually chassis with 350 engine once I get the motorhome apart and everything built detailed.

Now my question is did all '49 have reverse polarity?

The truck came with a 12v alternator already hooked up and no battery with all original wiring in the ignition system. Everything else looks original as far as I can tell besides a rats nest of wiring throughout which I'll redo if I can't get it running as is. I don't have a key for it so I disconnected the ignition and hotwired it. I hooked the battery up positive wire from the starter to positive on battery and neg to a bolt under the starter/block. Read 12v at the starter but no spark at battery when I connected the wiring and no spark when I hotwired it. I then hooked the battery up neg/pos and I got spark except something doesn't seem right here. I'm probably going to start redoing the entire wiring this week but I'm trying to figure out which way this truck is wired now after it's been messed with by PO's.


http://i1216.photobucket.com/albums/dd364/otservice/IMG_6995.jpg

Thanks,
Nate

Hy dubds10, I hope you have'nt fried the diodes in the alternator by hooking up the battery positive ground. Our Canadian GMCs are basically Chevys, and all but that largest Chevrolet Maple Leaf trucks are negative ground, if nothing is "on" in the vehicle you might not see a spark when you hook up the battery cables, hope that helps.

If you connected the cables in the positive ground position, you've definitely fried the alternator rectifier if you left it connected for more than a few seconds. There's no circuit protection to prevent a dead short through the alternator with the polarity reversed.
Jerry

No, the connections are too far gone to get a good solid connection anyways I was just touching them to see if anything would happen at the battery and ignition to see if there was power. Not that it really matters since I've got enough parts laying around to replace everything anyways. Was just mainly trying to figure out which way the PO wired this thing but I think I've figured it out now after I took a better look at the mixed up wiring. I'll be rewiring and cleaning up the engine bay tomorrow hopefully and get it driving by the weekend.

Thanks,
Nate