Low Air Pressure Warning Observation

[phat6]

Hope you guys had a great Thanksgiving! I smoked turkey for the first time and it came out great!

My M925A2 has had the low air pressure warning alarm going since I got it. Both gauges have shown good air pressure, so I was figuring I needed to replace one or both of the low pressure switches. Yesterday it was below freezing overnight and cold throughout the day. I fired the truck up to move it and after warming her up and releasing the parking brake, I heard . . . silence, no alarm. Not sure if the cold managed to unstick something in a failing switch, or if something else happened. I also do not know if the alarm will simply come back when the weather warms back up. I though the behavior interesting enough to post to see if anyone else had seen anything like this and if so, if they were able to trace down what exactly was happening and what needed to be fixed.

 

[jwaller]

Lucky you.

 

[Scar59]

Most likely the low pressure switch. The cold made something contract and break the short. It will most likely come back. Easy to T/shoot, easy to fix.

 

[BlueSkyPIC]

I had a similar problem when I received my M923A2. I had good pressure on both gauges. I started digging around into the manuals and found in manual TM 9-2320-272-24-1 page 2-158 (248 of 1020 PDF) a procedure to troubleshoot.

It ended up being a broken ground wire. (Number 57 wire in the manual)

Simple fix. Maybe check that wire.

 

[Triple C]

Remember that same alarm stays on all the time the parking brake is on.

 

[Suprman]

The alarm will sound but there are 2 different dash indicators one for parking brake and one for low air. The newer style switch can sometimes be disassembled and cleaned. The connections are Packard terminals sometimes unplugging and then plugging them back in will fix a bad connection.