The Stovebolt Site Forums The Shop Area The Electrical Bay 1949-53 GMC wiring info/diagrams

I recently scanned and cleaned up wiring diagrams from 1949, 1951, and 1953.
The 1949 and 51 are from original manuals. The 1953 diagram from a recent reprint sold as 1947-1954**
They can be found in this album. https://goo.gl/photos/H26qPfBHb7eS15698

The 1949 seems to use different color codes from the later trucks. Wire colors are on a separate page. This has more fuses in the fuse block than the later harness.

1951 info (all on one page, easy to read) differs slightly from the 49 diagram. The 51 diagram is fully included on the 1953 diagram with some other options then available.

I've noted in dark red on each diagram the printing date.

Don't overlook the COE diagrams because they include turn signals and trailer light harness wire colors and connections that could be useful to include in original fashion on your small trucks.

Grigg

** More info on the misleading 1947-1954 reprint , it is actually a 1953 manual and does/may not accurately reflect all years in all aspects, early wiring color codes for example.

Grigg, I really appreciate the photo link and the information. I am in the middle of my re-wire on my 51 and your photos are beneficial and I thank you🍻

You're welcome,
I need to start rewiring my 51 GMC, now I know what I want for a harness.
The stock pickup harness with added turn signals and trailer plug from the COE diagram.

Grigg

I was very surprised at how easy the stock harness (with turn signals and alternator) was to install. I have a good friend who purchased a $500+ Super harness a few months ago. We are in the process of tearing it all out and putting in the stock style harness.

Its way too cumbersome and way too complicated for your average enthusiast with no wiring experience, so he tried anyway with pretty much expected results. Too many connection points as opposed to total point A to point B connections. Sometimes simplicity is really the best. He is thrilled with his new harness and since there are no downsides, he will enjoy his truck for many years to come. Adding new circuits is so easy with the stock harness. I just did a how-to article on my 53 here:

http://www.devestechnet.com/Home/ADWiringSystem

Thanks for the wiring diagrams. You can never get enough info before embarking on a project such as this.