Low Air Alarm (Bell) Not working

[Dunk1954]

1999 Monaco Diplomat 38A. Air brake low pressure warning Alarm not working.
Just bought 2 weeks ago.So not sure if it was removed. I have looked very where under dash. The only alarm that comes on is the Leveling Jack .
Monaco Tech. was no help at all. Any help would be greatly appreciated.

[FIRE UP]

Originally Posted by Dunk1954

1999 Monaco Diplomat 38A. Air brake low pressure warning Alarm not working.
Just bought 2 weeks ago.So not sure if it was removed. I have looked very where under dash. The only alarm that comes on is the Leveling Jack .
Monaco Tech. was no help at all. Any help would be greatly appreciated.

Dunk1954,
Just wondering, have you ran a complete air system check? That is, run the air system all the way down to zero psi, then, with the engine at idle, watch the amount of time your compressor takes to build full pressure to the point at which the governor kicks out and the purge valve opens. Then, using your service brakes, WITH THE PARKING BRAKE OFF, stab the brakes again and again, 'till the system drops down to right close to 65 psi. At that time, THAT is when your low pressure alarm, usually a buzzer, not a "bell" (they want you to really hear that alarm) will come in and alarm you of low pressure.

Then, note whether or not you actually hear it, could be faint 'cause there's something obstructing it, who knows. Then, keep stabbing those service brakes 'till you hit around 45-30 psi where, your parking brakes should come on by themselves and, your little YELLOW knob on the dash will pop out.

That's your basic air system check. Now if you still don't hear any alarm at or about 65 psi, yep, you've got a problem. If the air system is building in an adequate time frame and, the parking brakes are self applying at the appropriate psi, then it sounds pretty much like you may have a defective low air warning buzzer.

Now, just where it's at in your coach, you'll have to go on a search and destroy (actually capture) mission. I suspect, it's most likely just inside the dash or very, very close by. Again, they (the air authorities) want you to hear it so, they won't hide it some place.
Scott

[tkcas01]

I wonder if they disabled it at the parking brake switch? On my Diplomat, that is in the console to the left of the driver. The real problem may have been the sensor going bad, so rather than replace that perhaps they just disabled the alarm.

I just replaced my sensor as it would alarm after getting under way, even when pressure was OK. Very annoying, but glad it is fixed now and working as designed.

[Dunk1954]

Originally Posted by FIRE UP

Dunk1954,
Just wondering, have you ran a complete air system check? That is, run the air system all the way down to zero psi, then, with the engine at idle, watch the amount of time your compressor takes to build full pressure to the point at which the governor kicks out and the purge valve opens. Then, using your service brakes, WITH THE PARKING BRAKE OFF, stab the brakes again and again, 'till the system drops down to right close to 65 psi. At that time, THAT is when your low pressure alarm, usually a buzzer, not a "bell" (they want you to really hear that alarm) will come in and alarm you of low pressure.

Then, note whether or not you actually hear it, could be faint 'cause there's something obstructing it, who knows. Then, keep stabbing those service brakes 'till you hit around 45-30 psi where, your parking brakes should come on by themselves and, your little YELLOW knob on the dash will pop out.

That's your basic air system check. Now if you still don't hear any alarm at or about 65 psi, yep, you've got a problem. If the air system is building in an adequate time frame and, the parking brakes are self applying at the appropriate psi, then it sounds pretty much like you may have a defective low air warning buzzer.

Now, just where it's at in your coach, you'll have to go on a search and destroy (actually capture) mission. I suspect, it's most likely just inside the dash or very, very close by. Again, they (the air authorities) want you to hear it so, they won't hide it some place.
Scott

Have Taken the dash panel out and no Alarm . Air system working fine ,brake lock at 58 psi. Monaco parts department knows nothing. Thanks for your reply Ill Keep looking

[tkcas01]

I wonder if the low air sensor can fail to NOT alarm at all? I have only heard of them failing such as to alarm when air is fine, but certainly seems logical it could fail the other way.

[FIRE UP]

Originally Posted by Dunk1954

Have Taken the dash panel out and no Alarm . Air system working fine ,brake lock at 58 psi. Monaco parts department knows nothing. Thanks for your reply Ill Keep looking

brake lock at 58 psi

Are you saying that your parking brakes come on, at 58 psi? That's not good. They're not supposed to self apply until the air pressure is lowered to very close to around 30 psi. I don't know if you've ever seen or read something like this but, just for your info, check out this link:
https://www.dmv.ca.gov/portal/dmv/?1...s/cdl_htm/sec5

There are quite a few air brake system descriptions and diagnostics out there in computer land and this is but one of them. So, at present, I'd keep digging for that buzzer and or, sensor that triggers it.
Scott

[jelag]

the only comment I'd add to FIRE UP is to check and drain the tanks before you start this test.... making sure you have full capacity in the tanks.... water takes up space that will not condense.... so you will loose air pressure faster... from lack of space in the tanks.... and chance the low pressure, and your e-brake/parking brakes apply....

One of the basic tests during a DOT test at a scale house is just as FIRE UP has outlined... BTW if it doesn't pass the complete test... the unit is red tagged (can't be driven from the scale house) until an on site mechanic has repaired and signed off the repair for the scale house... Its one of the most IMPORTANT tests that should be run before travel in anything equipped with air brakes....

In a dangerous situation you don't have to look at a gauges... you need the audio signal to identify your low on air...

[Dunk1954]

Thanks to Dave. Sent pic of alarm and part #. The manufacturer couldn't supply. Found connection in home where it had been removed. Went with after market alarm and wired in. Works great.
The previous owner removed evidently because of pressure monitoring on air tank. 20 dollar part that I replaced. Thanks for all response. Thanks

[tkcas01]

Congrats! Always a good feeling to solve these little issues and have things working right!