M52 Wiring Diagram

[mdemars03]

Im having issues with my brake lights and turn signals not working. I have already replaced the module, removed, cleaned, put back together, and reinstalled both the three lever light switch and turn signal lever. My head lights and tail lights work but not the turn signals (front and rear) or the brake lights. Does anyone know where I can find a wiring diagram for my M52A2 WO/W so I can start troubleshooting or would it be better to try and just find a new wiring harness for both the turn signals and brake lights and a new pressure switch for the brake lights? I know where the TM's are on the site but I just havent found a wiring diagram. Maybe I just overlooked it. Any help would be appreciated.

 

[steelandcanvas]

Have you opened up, inspected and cleaned the contacts on the turn signal switch? I believe the brake light circuit also runs through this switch.

 

[mdemars03]

If you are referring to the one on the steering column yes I have taken it apart and cleaned it. That and the three lever switch have been taken apart had the contacts cleaned and put back together.

 

[steelandcanvas]

I don't think it's the brake switch if turn signals and brake lights both don't work. But you can remove the plug to the brake light switch and jump the terminals and check the switch to see if you get brake lights. Examine the connector to the turn signal switch closely, look for broken wires in that connector. Not to insult your intelligence, but did you check the lamps themselves with a meter or visually? Wouldn't be the first time someone on this forum assumed the lamps were good.

 

[mdemars03]

I have checked the bulbs and they are good. I am tracing wires at this point to see if something is worn through and I am grounding out somewhere. No offense taken on asking if I checked though. We all miss things sometimes.

 

[mdemars03]

So looking more into the rear wiring harness I have quite a few bare and broken wires. Honestly I am suprised I even have tail lights working. Anyone know where I can find a rear wiring harness? From the looks of some of the older posts they are hard to come by. If not will a rear harness for a Deuce work? With all the damage I have found I dont know if it will be possible to fix. I know there may be some differences in the harness for stuff like the transfer pump but other then that is there a difference in the rear harnesses for my M52 and a deuce?

 

[steelandcanvas]

So looking more into the rear wiring harness I have quite a few bare and broken wires. Honestly I am suprised I even have tail lights working. Anyone know where I can find a rear wiring harness? From the looks of some of the older posts they are hard to come by. If not will a rear harness for a Deuce work? With all the damage I have found I dont know if it will be possible to fix. I know there may be some differences in the harness for stuff like the transfer pump but other then that is there a difference in the rear harnesses for my M52 and a deuce?

You may be further ahead by doing repairs, unless like you said, it's possibly replaceable with a Deuce rear harness. Repairs can be accomplished by replacing the bad wire segments, and using some in-line crimp connectors and heat-shrink tubing. I've had to replace a few bad spots and that is how I made my troublefree repairs.

 

[mdemars03]

You may be further ahead by doing repairs, unless like you said, it's possibly replaceable with a Deuce rear harness. Repairs can be accomplished by replacing the bad wire segments, and using some in-line crimp connectors and heat-shrink tubing. I've had to replace a few bad spots and that is how I made my troublefree repairs.

Looking online for a harness I am coming up empty handed so I may very well be repairing what I have. If thats what I need to do though that's what I do. It is a project anyway so I can take my time to do it and make sure it is done right. I'm hoping to have it driveable this weekend finally. Seems like every time I fix one problem something else comes up. Already replaced a head gasket, hoses, turbo, and had the injection pump rebuilt. Just have to replace the clutch this weekend and other then the brake lights and turn signals it should be ready to drive some finally.

 

[mdemars03]

Still looking for the wiring harness (slow day at work). Anyone possibly know the part number or NSN for it? It is the rear wiring harness.

 

[VPed]

Hey Matt, I know that the wire numbers and functions are the same between the deuce and your truck. If repairing the harness, use the deuce wiring diagram.

 

[steelandcanvas]

I don't recall if you ever got the Deuce schematic, but here's one for you:

View attachment WIRING_SCHEMATIC.pdf

 

[mdemars03]

Hey Matt, I know that the wire numbers and functions are the same between the deuce and your truck. If repairing the harness, use the deuce wiring diagram.

I was looking at that too. It looks like about the only difference I have found so far between mine and the deuce harness is the transfer pump for the right hand fuel tank. I know when we checked it the transfer pump works so it is just issues with the lights. I was looking at the wires the past few days after work and there are a bunch of bare wires at the tail lights.

 

[mdemars03]

I don't recall if you ever got the Deuce schematic, but here's one for you:

View attachment 548497

Thanks a lot! I had just been looking at the parts TM's so far.

 

[vtdeucedriver]

Deuce harness is not the same as a tractor. Your M-52 has not one but 2 trailer receptacles on that harness. The 2nd one is for your trailer on the 5th wheel.
Try finding a harness for the M818................if you cant find one, let me know.