Info needed: M37 CDN wiring diagram

[Dave Schindel]

I am looking for a legible copy of the M37 wiring diagram for the Canadian truck. I have downloaded the CDN repair manual but the wiring diagram is so pixelated that the circuit numbers are not readable. I also have the US diagrams but they seem to have used a different numbering scheme. If anyone has a clear, readable copy I sure would appreciate a copy.I think that a copy from a good quality camera would suffice. Thanks in advance for any help or advice!

[rob love]

The numbering system on smps is standardized. For instance, a headlight will always be 17, 18 and 91.
I had a look online at an American m37 wiring diagram, and the difference i can see mostly relates to the us use of the older style turn signal box from the 60s. In canadian service, the m37 would have just used a signal stat commercial signal arm with a 24v flasher and pilot lamp. I suspect the wiring diagram online would be for the m37b1.

One minor difference between the us and cdn trucks is the extra wire under the dash for the 24v dc outlet on the dash.

I rewired an m37 a couple years ago using one of the new old stock m37 wiring harnesses from John bizal. It covered the dash area as well as under the hood up to the headlight connections and to the connections under the right side going to the master cylinder and taillights.

[Dave Schindel]

Rob, thanks for the clarification. I just got a NOS wiring harness and the circuits are indeed numbered the same. That's going to simplify things a bit.

[rob love]

Where it gets a little goofy is when they add the turn signals to the harness. For instance, 460 (right turn) and 461 (left turn) are added to the existing lamps for brakes, or in the case to the front park lamps on the 3/4 ton or deuce. So the normal 22 wire which would be for the brake lamp(s) at the rear now has a dual purpose as turn signal as well. So left turn/brake becomes 22-461 and right turn/brake becomes 22-460. Notable that there was originally only one service brake lamp on the rear. Originally the army added a round lamp unit with a single bulb on the right rear for the turn signals and there was no rear right marker lamp, however over time a lot of these vehicles got a regular service taillamp installed along with a seperate blackout brake marker.

The modification instruction for installation of the signals just had you running some white commercial wire where the extra wiring to the rear was required. Generally though, most restorers will use the mil-spec wire and incorporate it to the rear harness.