M931A2 CTIS stopped working

[bulldog_mack13]

Its the part circled in red correct?

 

[Suprman]

There are 3 switches in the tank area by the air petcocks. One on each of the 2 air tanks they are for the low air warning and one switch for the ctis. If you look in the TMs at the low air warning system and identify which 2 are for that then the one left will be for the ctis. You can also let the trucks air fill up, shut off the truck but leave the battery switch on and the ignition on run without starting the engine and unplug the air switches one at a time. When you unplug one of the low air switches the low air alarm will come on. If someone in your are has an a2 truck you can swap in their controller to see if that's the issue.

 

[Suprman]

The part you circled looks like an air safety valve probably set to vent off excess air at around 150psi. Before the abs mods were installed I think more trucks had the safety valve there. The air dryer should have one also now.

 

[bulldog_mack13]

TM9-2320-272-23-1 page 257 looks like the thing I circled in red in the picture but Im going to look around and see if I can find the ones your talking about,

update , I know what the low air pressure switch looks like, we had to change one on a friends truck. Im still not locating the CTIS one.

 

[Suprman]

The low air switches look like this except they are probably covered with green carc. I think the ctis one looks similar.

 

[bulldog_mack13]

Roger that , I found that , mines a little diff but same thing pretty much.

I didn't see the CTIS one near it. And nothing in the manuals says anything about that part.

 

[Suprman]

No I have never seen a manual that shows more than a block diagram of the system. Nothing that shows physical location. But it's down there by the other two. It has 2 wires coming out of it. There isn't much else down there like that.

 

[bulldog_mack13]

Is there anyone that can post a picture or help out, im going to try a few other things tomorrow but this part sure seems like the cause of the issue, would be nice to fix the easier things. Jay

 

[Suprman]

I will find a pic tomorrow. It's too dark out now.

 

[bulldog_mack13]

Thanks a ton , il stand by .

 

[Suprman]