Low air/parking brake buzzer inop but warning lights work

[2mtrucks]

As the title says, buzzer inop but warning lights work correctly and shut off at the appropriate pressure/parking brake disengagement. I always look at the gauges anyway but as annoying as this buzzer is I need to get it working. Is the fix replacing the FSWM or am I missing something here? I have combed through this forum for a couple hours but haven't seen an identical situation. Thanks.

 

[Suprman]

Replace the module. I saw one of the newer type modules where there is a hole in the front and you can see the piezo buzzer someone had intentionally "deactivated" it with a screwdriver or something.
Will

 

[gungearz]

The buzzer module is bad... went out on mine a year ago and I think it's great being not working and hearing the annoying buzz... I sit and let my truck idle for 5 to 10 minutes before I take off... check all gauges before I put it in gear and go if all is well.

 

[73m819]

The buzzer module is bad... went out on mine a year ago and I think it's great being not working and hearing the annoying buzz... I sit and let my truck idle for 5 to 10 minutes before I take off... check all gauges before I put it in gear and go if all is well.

That LOW AIR BUZZER is a saftey item that is REQUIRED to work by law, be DESIGN it is a attention getter.

 

[gungearz]

That LOW AIR BUZZER is a saftey item that is REQUIRED to work by law, be DESIGN it is a attention getter.

Yup... since I'm the only one in my truck. I will modify it on how I like.... the flag works which what matters but if I had a fleet and let someone else drive my truck... then it's a concern... but to me on my truck... I like it the way it is.... if you want, your more then welcomed to come by and take care of it... I'll supply the beer.... and we'll share some stories....

 

[Rifleman]

2Mtrucks, i posted this same problem with my truck on the form months ago and never got an answer. When you find out what is wrong with your's let me know because mine has the same problem. I bought a replacement FSWM from another member here and that didn't fix the problem so mine still has the same problem. Now i can see one FSWM being bad but two in a row i just don't think that's my problem now.

 

[Suprman]

Check the ground on it. Bad grounds are notorious problems with military stuff.

 

[juanprado]

Artisan did a extensive thread on it.

My lights all go off appropriately: parking brake switch & light works on /off ok, air brake light goes off when pressured (both tank switches appear to be working properly) but the annoying buzzard will not shut off. On box #3 and I can't figure it out.

My research tells me the early models with the temp light were also wired through it.

It seems to be extremely common m939 issue.

I have tried 2 different styles of boxes. a smooth plastic and a ribbed metal. I saw on ebay a 3rd style that was plastic but slightly different shape than mine ( more boxy and angular). It sold before i could make my mind up to dump more money on it.

For now, mine is also unplugged till a solution can be found.

 

[Suprman]

On one truck I had the buzzer would buzz when I put the light switch in blackout mode. Turned out to be a bad ground on the left front blinker housing. I re-grounded all the lights on the truck. I sanded spots and added ground wires and bolted them down with lock washers then painted over them. Problem solved. The lights were still coming on just a little dimmer than they should have been. They were finding a ground somehow thru the parking light circuit. I finally figured it out when I had the blinkers on and the left front parking light was blinking with the blinker.

 

[tobyS]

I'll trade one that won't go off for one that is silent.

 

[2mtrucks]

I will do some investigating this weekend for grounds, connections etc. Don't really want to spend $200 unless it solves the problem.

 

[2mtrucks]

I got lucky...the FSCM has a small hole about 1/8 inch or so and all sound emanates from that hole (at least on my A1).I was looking at another truck with a working low air alarm and if I covered the opening on the FSCM tightly with my finger it went silent. So today I got a dental pick and gently scraped the opening and it began working. Obviously there was some obstruction...insect residue, mud or maybe a manufacturing defect...not sure what it was.

 

[Suprman]

Maybe it was intentionally made inop by the prior operator.

 

[2mtrucks]

Yes...that is possible also. I would rather it worked just in case.

 

[frioman]

The TM states, "WARNING ALARM BUZZER is located above left cowl vent." My truck is 10 miles away at the moment or I would simply go look, but I'm assuming they're talking about the vent inside the cab near the driver's left leg. Is this correct? Thank you.

 

[2mtrucks]

Correct. Located about an inch above the screen of the driver's side cab vent.

 

[frioman]

Correct. Located about an inch above the screen of the driver's side cab vent.

Thanks for the quick reply.

 

[two.fiveM35]

Thanks for the useful info, I have the same issue on my 2010 RRAD M923a1 that I need to look into.

 

[marchplumber]

My buzzes alright, but darn parking brake light is inop most of the time, low air pressure light almost ALL of the time, except when very cold. Does that make sense to anyone?

God bless,
Tony

 

[juanprado]

My buzzes alright, but darn parking brake light is inop most of the time, low air pressure light almost ALL of the time, except when very cold. Does that make sense to anyone?

God bless,
Tonh

I believe you have multiple problems. The parking brake light is a small flat metal switch in the parking brake handle assembly. Other problem could be a low air pressure switch (2 of them) , the box or ground issue.