Trying to id a buzzing sound

[obxron]

Newbie question. I'm still figuring out the various noises and quirks with my M35A2. I noticed after the warning buzzer shuts off there is a higher pitched buzz that starts and continues even after the truck is shut off and slowly the buzz dies out. Would that be pressured air escaping from somewhere, is this a normal sound? The truck runs and stops fine ,all the guages are reading properly. Thank you for any answers

obxron
1954 M37
1968 M101A1
1968 M35A2

 

[NDT]

If is coming from under the truck, it is the safety pop off valve on the air tanks. Check your compressor cut out on the firewall, it is not functioning.

 

[obxron]

I should have said that the buzz was coming from the firewall area, I guess that would still be the compessor cut out? Thank you NDT

 

[NDT]

The cut out does not normally buzz, it clicks when it kicks the compressor on, that can happen minutes, hours, or days after you shut the truck off, depending on how tight your air system is. Sounds like your has issues. If air is coming out of it somewhere, replace it, it is a safety critical device. (brakes)

 

[dentman]

nOOb inquiry; so you guys are saying that when after engine shutdown, a slow, and increasing hiss of air followed by a pop off sound to silence is a safety issue? Time to dig into the TM's

 

[54reo]

nOOb inquiry; so you guys are saying that when after engine shutdown, a slow, and increasing hiss of air followed by a pop off sound to silence is a safety issue? Time to dig into the TM's

No, what you just described is the sound of a normal air governor signaling the air compressor to engage as the pressure in the air system bleeds down. But since the engine is not running in your case, it simply goes quiet.

 

[groundog]

check under the dash on the firewall---there is a switch that operates the buzzer---they go bad and leak air thru a little hole on the side of the switch---you should find a wire leading from it to the buzzer----groundog