M923A2 air warning buzzer starts less than 120psi???

[engele]

Hi together,
i have a question. Can´t find something in the manual or at the search function at the forum.
My air warning light and buzzer start if i brake 2 times and the pressure falls less than 120psi. Per brake push i lose about 5-10psi.
Can i adjust something? The buzzer should start at about 65psi. Or the the buuzzer goes on if i lose to much air too? I think it´s only on/off function at XXpsi and not how fast they lose the pressure.

Best regards Alex

 

[Hoefler]

Mine does the same thing. Seems to happen more when its cold out. Waiting to here others chime in on reason-solution.
Pete

 

[74M35A2]

Correct, it should trip < 60psi.

 

[juanprado]

The fail safe warning control module is suspect. They are known to be a pain. The new style 5 part repair tm series have great work packages for step by step troubleshooting.

primary and secondary air tanks have a pressure warning switch but as stated it is supposed to be 60 psi or so.

 

[engele]

mmmhhh ok than i will try the tm? Is there available for download? I think have only the older one.
Attached a pic from my A1 with my JK.

 

[MtnSnow]

Yes the TM's are in the stickies

 

[Suprman]

If its the newer style switch and that is diagnosed to be the issue there is a small
hex screw on the side the switch can be taken apart and cleaned.

 

[tractors0130]

Faulty low pressure switches on the primary and secondary air tanks can cause your low pressure buzzer to alarm even when there is enough air. You can make a Packard jumper connection and temporarily jump either one or both of the switches when your air pressure gauges are up on the dash to troubleshoot. The pressure switches are normally open when the pressure is low and closed to ground when there is sufficient pressure. You can also verify the switches with an ohm meter when there is full air pressure and the low pressure buzzer is buzzing.

 

[engele]

Hi guys,

you're right. Was only the adjumstement screw on the Switch!
thanks a lot o all!

 

[Artisan]

Faulty low pressure switches on the primary and secondary air tanks can cause your low pressure buzzer to alarm even when there is enough air. You can make a Packard jumper connection and temporarily jump either one or both of the switches when your air pressure gauges are up on the dash to troubleshoot. The pressure switches are normally open when the pressure is low and closed to ground when there is sufficient pressure. You can also verify the switches with an ohm meter when there is full air pressure and the low pressure buzzer is buzzing.

There is a really short ground wire on the primary and secondary air tanks switches to frame (On my A1) you need
to make sure it is grounded correctly as well. Was it a 55 wire? I forget.

 

[Big Tex]

Training Manual NEEDED for my 1990 M923A2.... where can I down load one?

Thank you!

 

[MtnSnow]

Read thru the postings to get the different TM's
http://www.steelsoldiers.com/showthread.php?121487-TMs-for-M939-Series-Trucks