Low air pressure alarm not working.....

[67 evil eleanor]

My alarm is not working and I'm not sure how to fix it. I can trace a wire from the junction behind the dash where I guess a air pressure sensor would be hooked but I don't see a wire that provides power. How many wires go to this and where does it pick up power if it does. I am building around 90 PSI according to the gauge but have no warning when I start the truck up.

 

[JCKnife]

I am no good at reading wiring diagrams but you can find one in TM 9-2320-361-20 page 2-120 (which is page 206 in the PDF file)

 

[Wildchild467]

I think the power comes from one of the wires that comes though the firewall on the drivers side. It plugs into the air pressure sensor mounted inside on the firewall. another wire comes out of that and plugs into the buzzer mounted inside on the firewall. Did you check to make sure all the wires are plugged in? With the truck shut off and air drained, turn the power on and see if you have power to the wire that plugs into the warning buzzer. if not, then just trace the power back. I know the buzzer in my M109 did not work when i bought the truck, then all of a sudden one day, it started working and has ever since. I think there are some breaker points in the buzzer that get corroded and if it starts to work, it will eventually clean themselves up and start working better. I think the low air warning buzzer might be the only thing on a deuce that will fix itself (providing there is power going to the buzzer)!

 

[Heath_h49008]

Most were unplugged for long periods of time. Make sure the wires are on and have power with a test light. Check for the switch's function, and then tap it with the handle of a screwdriver.

Although I'll wager you'll unplug it a week after it starts working normally.

 

[Wildchild467]

Mine is still plugged in. Then again, mine holds air real nice. Takes a long time to track down lots of little leaks.

 

[67 evil eleanor]

Thanks, I know where I was missing it now. I believe the wire that goes to the switch is unplugged. I'll see if I can find it.

 

[JCKnife]

Wow I would never unplug mine! Why would you do that? I'll take a few seconds of annoying noise over unexpected breakdown / big problems without warning.

 

[rosco]

DOT likes to see the buzzer come on @ exactly 60 psi, and feel very positively that that one feature, is the best "CASH COW" they have! AND, they won't care wether a CDL, is required or not. Probably, only driving without brakes, would equal not have a working low air buzzer!

 

[RedbeardTheZombieHunter]

Mine quit working one day, so I reached under the dash, found the wire to the buzzer and moved it around. The buzzer came back on, but I have either a loose connector or a dirty contact point. Either way I need to take out the passenger seat to make room enough to get my big carcass under the dash to fix it properly. Yee haw!

 

[frank8003]

low air pressure buzzer

low air pressure buzzer
I found when seeking lift pump trouble that the wire going to buzzer has obviously been yanked on. I wiggle the wire around and it works for long time.
I installed alternate gauge also in line of sight.

 

[frank8003]

air pressure buzzer wires

look in here

 

[Deuce007]

Under the dash of your truck you will be able to see what is shown in the picture. I had this problem too but mine was an easy solution. Hook the wire with red dot in the picture shown below to the pressure sensor with a red dot and it should work. (P.S. the air vent tube hooked up to the heater might be in the way so you might have to unscrew the clamp and move the hose out of the way.)