Low Air Dash Light & Buzzer

[WaynBo]

I purchased this 2006 Monaco Cayman one year ago and the previous owner mentioned that the low air light and buzzer would activate for no apparent reason. He disconnected the buzzer at the dash (which is fine with me because i can't hear it anyway). I have been trying to solve the issue with no luck. Has anyone else had a similar experience?

[Tom Cherry]

Assuming you do NOT have low air.  On my Camelot, the alarm or input wires completed a “ground” circuit.  Thus when you have a true low air, the switch will ground out one side to a chassis ground….and then the wire from the switch runs to the dash cluster or “brain”.  Typically, because Monaco had a variety of dash cluster vendors, there is one central unit or brain that drives the dashboard with the idiot lights.  The same brain sends signals to the gauges.  So an oil pressure gauge has a variable inout and the brain passes it to the oil pressure gauge.  Now SOME variable gauges may be direct connections….but mine geed through the brain.

I would find out “how” he disconnected it. If he killed the “buzzer” or chime, then he may have killed all other alarms.  Typically the brain will send a signal to the audible buzzer or whatever…..to alert you….then the proper idiot light will come on.  You probably will get an idiot light, but no noise. BTW, even with something re$olution hearing aiid$….I can hear mine….but it drives DW crazy.

One theory is you have a chafed wire….so the right Highway with maybe a few bumps and the right speed, will vibrate or displace the air wire and it shorts  or gets grounded.  Fix might be to look at prints.  See where the signal wire starts its journey back to dash and pull a temporary wire….and disconnect old on both ends.  Get the Dash manufacturer and model number.  Call them.  They should have a print and show what number or color wire on the cluster you are looking for.  Then snip and crimp in the new wire.

[Rodger]

I have sort of a similar issue.  Sometimes even with full air pressure, the buzzer/beeper will go off like it has low pressure when I first disengage the air park brake and put it in gear.  It will go off for anywhere from 15 seconds to 5 minutes and eventually will stop.  Other times it will just come on.  What I have found odd is if I disengage the air park brake, let off of the brake pedal and make the beeper go off a couple of times, it won't come on when I put in gear and let out of brake.  It's like sometimes it gets reversed on what engages the alarm.  Sometimes when it is going to mess up it will beep and go off when I push the brake.  But on my last trip I made sure to push the park brake button, let out on brake and even let the coach roll a little, then push the brake, put it in gear, then let out on the pedal and no alarm.  Worked almost every time.  Weird, but something is getting crossed up/confused on what tells it to activate the alarm.

Edited April 13 by Rodger

[WaynBo]

55 minutes ago, Tom Cherry said:

Assuming you do NOT have low air.  On my Camelot, the alarm or input wires completed a “ground” circuit.  Thus when you have a true low air, the switch will ground out one side to a chassis ground….and then the wire from the switch runs to the dash cluster or “brain”.  Typically, because Monaco had a variety of dash cluster vendors, there is one central unit or brain that drives the dashboard with the idiot lights.  The same brain sends signals to the gauges.  So an oil pressure gauge has a variable inout and the brain passes it to the oil pressure gauge.  Now SOME variable gauges may be direct connections….but mine geed through the brain.

I would find out “how” he disconnected it. If he killed the “buzzer” or chime, then he may have killed all other alarms.  Typically the brain will send a signal to the audible buzzer or whatever…..to alert you….then the proper idiot light will come on.  You probably will get an idiot light, but no noise. BTW, even with something re$olution hearing aiid$….I can hear mine….but it drives DW crazy.

One theory is you have a chafed wire….so the right Highway with maybe a few bumps and the right speed, will vibrate or displace the air wire and it shorts  or gets grounded.  Fix might be to look at prints.  See where the signal wire starts its journey back to dash and pull a temporary wire….and disconnect old on both ends.  Get the Dash manufacturer and model number.  Call them.  They should have a print and show what number or color wire on the cluster you are looking for.  Then snip and crimp in the new wire.

I do have plenty of pressure so I'm not too worried about the light. The previous owner just unplugged the buzzer behind the dash. if i hook it back up it chirps once again.

43 minutes ago, Rodger said:

I have sort of a similar issue.  Sometimes even with full air pressure, the buzzer/beeper will go off like it has low pressure when I first disengage the air park brake and put it in gear.  It will go off for anywhere from 15 seconds to 5 minutes and eventually will stop.  Other times it will just come on.  What I have found odd is if I disengage the air park brake, let off of the brake pedal and make the beeper go off a couple of times, it won't come on when I put in gear and let out of brake.  It's like sometimes it gets reversed on what engages the alarm.  Sometimes when it is going to mess up it will beep and go off when I push the brake.  But on my last trip I made sure to push the park brake button, let out on brake and even let the coach roll a little, then push the brake, put it in gear, then let out on the pedal and no alarm.  Worked almost every time.  Weird, but something is getting crossed up/confused on what tells it to activate the alarm.

I did replace my park brake valve last summer. Its works much smoother but did not solve the issue.

There is one pressure sender on each air tank I assume that when pressure reaches a set value the pressure switch grounds out the sender completing the circuit? Not sure how to check them? I cleaned them up but no change.

[WaynBo]

It looks like new switches are only $40 so i will probably order 2 and install them and see what happens next week?

[Yoaks5]

You should be able to do a continuity test (horse shoe looking symbol on a digital volt meter). Dump air from tanks and test the across the terminals and do the same with it aired up. You should have continuity on one of these tests and not the other depending if it's a NO or NC switch. 

[WaynBo]

4 hours ago, Yoaks5 said:

You should be able to do a continuity test (horse shoe looking symbol on a digital volt meter). Dump air from tanks and test the across the terminals and do the same with it aired up. You should have continuity on one of these tests and not the other depending if it's a NO or NC switch. 

Just checked the continuity of the senders and they appear to be working ok. (Looks like normally closed). I am now puzzled why both terminal wires are grounded? I would think that one should be grounded and the other going to the dash light/buzzer? I may need a wiring diagram now to see where these wires go?

[Tom Cherry]

7 minutes ago, WaynBo said:

Just checked the continuity of the senders and they appear to be working ok. (Looks like normally closed). I am now puzzled why both terminal wires are grounded? I would think that one should be grounded and the other going to the dash light/buzzer? I may need a wiring diagram now to see where these wires go?

I can’t explain that and may have misunderstood your post.  Bottom line, a GROUNDED signal is sent to the dash brain or whatever triggers the Low Air alarm.  There are many topics on the various switches on the air lines.  MEMORY….as well as not being an expert.  You CAN get a low air signal from one or other of the brake (Treadle Valve that applies the air brakes).  Those are typically the type that come on or close a contact when you have less than 50/65 PSI.  
 

It would be good good to look at the prints.  Unless you have a pressure switch that is “funky”, as in closes momentarily when something vibrates, then I still lean to a chaffed wire….but checking the circuit and seeing if it works properly,  when fully aired to partially….to zero is critical.  You want to bleed down the air to see if the parking brake will not release below say 50/65 as well.  If all the switches are working and the circuits are good….then the gremlin has to be a chaffed wire.  My gremlin would come and go and it was a wire in a bundle in a tight corner.  Chaffed and not really accessible.  I ended up “pulling and tugging” until I relieved the strain and got the whole bundle away from the chassis member.  That was in 2012….and never a peep since then…or almost 50K mikes….so I do have a wee bit of experience….  LOL…I was LUCKY!

[WaynBo]

15 minutes ago, Tom Cherry said:

I can’t explain that and may have misunderstood your post.  Bottom line, a GROUNDED signal is sent to the dash brain or whatever triggers the Low Air alarm.  There are many topics on the various switches on the air lines.  MEMORY….as well as not being an expert.  You CAN get a low air signal from one or other of the brake (Treadle Valve that applies the air brakes).  Those are typically the type that come on or close a contact when you have less than 50/65 PSI.  
 

It would be good good to look at the prints.  Unless you have a pressure switch that is “funky”, as in closes momentarily when something vibrates, then I still lean to a chaffed wire….but checking the circuit and seeing if it works properly,  when fully aired to partially….to zero is critical.  You want to bleed down the air to see if the parking brake will not release below say 50/65 as well.  If all the switches are working and the circuits are good….then the gremlin has to be a chaffed wire.  My gremlin would come and go and it was a wire in a bundle in a tight corner.  Chaffed and not really accessible.  I ended up “pulling and tugging” until I relieved the strain and got the whole bundle away from the chassis member.  That was in 2012….and never a peep since then…or almost 50K mikes….so I do have a wee bit of experience….  LOL…I was LUCKY!

Im leaning towards a chafed wire also but i have no system diagrams. Im on vacation with it now and hope to be home in another week at that time i can really start pulling on wires? Thanks