Just bought a M931A2 and need some Assistance

[Brian46]

I am trying to figure out what was missing from the air system in my M931A2, the truck came from GL with an air leak when you applied the brakes, upon further inspection it appears a part was robbed from it and was causing the leak. A plug was put in place and the system works fine, but I think it was a sensor or switch that is missing and would like to confirm exactly what I need before just buying parts.

Here are a few pics, the fitting that required a plug (green plug in picture) is on the inside of the drivers side frame right next to the rear output of the transfercase. there are two loose wires there as well, that is what makes me think it was a switch of some kind that is missing.


Any help in identifying the part I need, or if you have one/know where to buy would be much appreciated.

Thanks

Brian

 

[juanprado]

Do your brake lights work? Looks like the brake light switch port and 2 wires?

What are the tag numbers on the wires?

The p2p software has a great air and wire diagram flow charts.

 

[Brian46]

Do your brake lights work? Looks like the brake light switch port and 2 wires?

What are the tag numbers on the wires?

The p2p software has a great air and wire diagram flow charts.

You are correct, I thought they worked but the guy following me home must have been sleeping the whole way because he thought they did lol

Thanks a lot

 

[droprat]

Part

Hey Brian

I will take a look and see what i have.

I dont have any of the front shackles or mounts.

Thanks

Rich

brake lights work

 

[droprat]

Brian

Looks like i found part. But its on driver
Side. Looks like its two parts attached
With a threaded coupling. The part closest
To the frame has the following info metal
Tag

278614

DC-4.

PM your email and i will send you
Some pics

Rich

 

[Artisan]

Is it a missing;

SPRING BRAKE WARNING LIGHT SWITCH
- Activates warning light when spring brakes are engaged


Does the red light flash when you set the e-brakes on the dash?
If not I might be onto something.

Start reading TM / 24-1 on page 67, at page 75 i think I saw your missing deal.

DO NOT COUNT ON MY INPUT. Read it and be sure...

To find a leak "I" added a 1/2" NPT "T" at a pressure relief valve
my truck has BEFORE the air dryer. Add a T and reinstall the PRV
and add a Shrader / Air fill valve... NOW you can pressurize
the system from your shop air compressor and not have to have
the engine running and you can listen for leaks.

 

[Brian46]

Brian

Looks like i found part. But its on driver
Side. Looks like its two parts attached
With a threaded coupling. The part closest
To the frame has the following info metal
Tag

278614

DC-4.

PM your email and i will send you
Some pics

Rich

Thanks, PM sent

 

[Artisan]

Brian does the red light flash when you set the e-brakes, the light on the dash?

 

[Brian46]

Brian does the red light flash when you set the e-brakes, the light on the dash?

Yes it does, I figured out it is the brake light switch. So I need two switches, one for the low air and one for the brake lights.

 

[juanprado]

The parking brake switch is in the parking brake handle. There is an air switch and a small electric contact point switch.

The spring brake pressure switch is behind the dash on a T of the spring brake over ride valve.

The 2 low air pressure switches are on the air tanks.

The stoplight switch is on the driver's side frame.

I am stumped on what this one is?

Rich,

Can you post your pic?

 

[Brian46]

It is the stoplight switch on the frame that I need that was missing.