The Stovebolt Site Forums The Shop Area The Electrical Bay '53 GMC Rewire

I bought a '53 GMC 1/2 ton last weekend. It runs and drives great. The problem is that a previous owner, in an attempt to upgrade the truck, put in a 12 volt battery and coil, and wired the coil to a toggle switch on the dash. This done, they removed ALL of the rest of the wireing from the truck. No horn, no gauges, no chargeing system, no lights, NO WIRES! I'm itching to rewire the truck but I have a lot of questions(most you've heard a million times). To start off I do have a wire diagram for the truck but it looks to me like ALL of the power to everything goes through the ammeter before going anywere else. Am I reading this right? If I run 12 volts through the ammeter it will fry it, right? If someone could walk me through this whole thing useing simple (second grade) terms that would be great. Thanks

The ammeter measures amps not voltage. It will work exactly the same with the 12 volt system.

All you need to do us buy a new correct wiring harness for your truck and install it.

Thanks truckernix, that makes perfect sense. I love the look of my original gauges, what can I do to use them without ruining them (assumeing they even work)? If I use voltage reducers, do you have a suggestion of brand or part number? Also, would you recommend useing an alternator or converting the generator to 12 volt? I hope to use this as a daily driver. I will not be useing power accesories like windows, locks etc.

By the way, thats a real sweet job you did on your '51 1 ton.

Thanks again

Nix is right, it will go through the amp. meter. I would use an alt. but not a high powered one. About 65 amps. max. That amp. meter is designed for about 30 amps. The best reducer for gauges is the Runtz. It uses 1 for each gauge but the only one you will need it for is the gas gauge.

Thanks for the kind words. There were some years when GMC used an electric temperature gauge, I believe it was. That is why I used the word "correct" describing the harness because there were differences between GMC and Chevy. On the Chevs, the two components to worry about with the 12v conversion would be the blower motor and the gas gauge. The starter should work fine on 12 and of course all the bulbs get changed.

What you must do before you hook up your 12 volts is to put a resistor in the fuel gauge line. 12 volts going through that will fry it in a milisecond!
I think the idea of wiring the coil to a toggle switch may have been an attempt at theft prevention. Its an old trick but it works.
As to rewiring I have done mine without a wiring kit. If you have the schematic you are in good shape. On it there are specs for the wire thickness (gauge) and its for 6 volt. You can use that gauge for a 12 volt or even go one size smaller.
The wiring on my 49 Chevy was pretty simple. I had the original wires so it was easier than what you have to face. I started at the fuse box which is different to yours and went forward to the lights, etc. From there I just did one wire at a time. Good crimped connectors (a good crimping tool is a must) and cleaned up the posts I was attaching to and in some cases put heat shrink over the terminals. Do not solder your connections as vibration could make them fail. You will be surprised how easy it is - until you have to crawl upside down to get to those gauges under the dash.

I had to rewire my whole truck too. I found an awsume wiring kit at http://www.americanautowire.com/
All switches were included some were the brake switch,hight beam floor switch, a signal light toggle switch for under dash. all proper connectors to put everything back to speck came with it..(Taillight loom covering and proper boots to fit into the lights) It was a little pricey but in the end well worth the money and frustration finding everything I needed. Just a little advice, this has been my fourth Truck to completly rewire and I've tried several different kits!

I just need to rewire my ignition switch on my 53 3100 half ton, it has three connectors on the back, where should the wires go from these connectors, thanks,