New member w/questions

[Pearat]

Hello from Oklahoma

I just bought a 1952 GMC M135 not too long ago. The technical manual posted here has been invaluable so far. The 302 runs good, but the trans will only get 1st and reverse. I'll be trying to address that soon, but right now I'm in the process of replacing the battery cables and batteries. Here's my dilemma: I have two switches on the left side of the dash. One powers up the electric fuel pump mounted in the engine bay. The other one has 4 wires coming out of the back and it seems to power just the ignition system. Two of the wires are cut, but not terminated (I'm sure that's safe). One of the other 14 guage (I think) wires is connected two a 2/0 cable grounded to the dash. The other wire is connected to another 2/0 cable connected to the negative terminal of the drivers side battery. Can anyone make sense of this? I'm having a little bit of a hard time deciphering the electrical diagrams but it sure isn't meant to be like this. Any suggestions are appreciated.

 

[SturmTyger380]

Welcome to the Early Deuce forum. We love pictures! Let us see what you have.

The electric fuel pump switch was added. Does the pump in the fuel tank still work? I would guess not since they added one under the hood.

The other switch should be the (3 connector early switch), 4 connector power switch to turn the truck on. There should be one wire (#11) coming in from the voltage regulator and the positive battery terminal of the passenger side battery, (Early M135 only voltage regulator). This is the source of power.

Then there should be at least two wires going out, one to the distributor (#12) and the other wire (#27) to the spider wire harness behind the gauge cluster. There should be another wire connected in with the (#27) wire that goes to the low pressure air switch (#85).

May times the forth one on the newer switch is not used but to keep from having an open position on the switch a connecter is installed that runs a wire to a dummy connection that is attached to the dash. It’s not really grounded out.

 

[USMC 00-08]

Hello and welcome to the forum! I'm not too far from you looks like.

I also have the same year and model of truck with the same transmission issue in low range, but it dies when I put it in high. Just moved out here last year and my truck is supposed to be getting shipped out here this summer.

If you figure out the transmission issue before I do, please post what you found.

My truck is my avatar.

 

[Pearat]

Thanks SturmTyger. That clears things up. Looks like I'll be doing some light rewiring. My truck looks a lot like USMC 00-08's except the bed is also orange. Maybe they came from the same forestry service auction. I'll post some pictures as soon as it stops raining.

 

[Pearat]

Here are the photos. Sorry for the delay.

 

[SturmTyger380]

Nice truck! You have really clear window glass there. Humm... even the interior got painted. Are you going to go back with the original paint color?

Alan

 

[Pearat]

Thanks for the compliment. Yeah, I'll probably go back green with it. The orange wouldn't be too bad for a while but all of the forestry service insignia were painted over with some weird fuchsia color. It looks a little strange with all of the purple-ish patches.