Mackman686 Posted 21 hours ago Share Posted 21 hours ago Hi all, I’ve got a problem on my hands. My low air buzzer is going off all the time in my 1990 Mack RB688RST nz model. I’ve replaced and now unplugged the new air pressure switches on the fire wall and the buzzer is still going off. The only way to stop it is by pulling the circuit breaker out or turn the key off. Any help would be much appreciated, photo below of the truck and the buzzer set up. Thanks again 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76547-low-air-buzzer-going-off-all-the-time/ Share on other sites More sharing options...
Popular Post Joey Mack Posted 15 hours ago Popular Post Share Posted 15 hours ago Isnt that a multi buzzer? It also sounds out with the turn signals, right ? And power divider if you have a locker. ? 3 Quote Link to comment https://www.bigmacktrucks.com/topic/76547-low-air-buzzer-going-off-all-the-time/#findComment-594116 Share on other sites More sharing options...
Mackman686 Posted 6 hours ago Author Share Posted 6 hours ago 8 hours ago, Joey Mack said: Isnt that a multi buzzer? It also sounds out with the turn signals, right ? And power divider if you have a locker. ? Yeah it is a multi buzzer, low oil pressure, low water, low air, power divider, and the turn signals. Quote Link to comment https://www.bigmacktrucks.com/topic/76547-low-air-buzzer-going-off-all-the-time/#findComment-594126 Share on other sites More sharing options...
Joey Mack Posted 6 hours ago Share Posted 6 hours ago Does it cut off if you unplug the turn signal switch, ? I am leaning towards an electrical backfeed... due to a grounding issue.. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76547-low-air-buzzer-going-off-all-the-time/#findComment-594127 Share on other sites More sharing options...
Mackman686 Posted 5 hours ago Author Share Posted 5 hours ago 1 hour ago, Joey Mack said: Does it cut off if you unplug the turn signal switch, ? I am leaning towards an electrical backfeed... due to a grounding issue.. Nah I haven’t unplugged the turn signal, it’s brand new aswell and never had this issue until I’ve started putting everything back together in the truck. I’ll try that though cheers Quote Link to comment https://www.bigmacktrucks.com/topic/76547-low-air-buzzer-going-off-all-the-time/#findComment-594129 Share on other sites More sharing options...
Joey Mack Posted 4 hours ago Share Posted 4 hours ago With the pressure switches being new, do you have the normally closed and normally open switches in the right spots? But you did say with them unplugged it still sounds out.. still leaning towards a backfeed... 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76547-low-air-buzzer-going-off-all-the-time/#findComment-594133 Share on other sites More sharing options...
BottleHauler84 Posted 1 hour ago Share Posted 1 hour ago Does your shut down light in the dash work or come on at all or stay on? I had this same issue on my 88. Not sure if yours does, but If your truck has the Kysor shut down system, theres a sensor on the coolant manifold on the drivers side of the engine with 3 wires. Mine was located at the rear of the water manifold. Mine was corroded and shorting out. Might give it a look. Alot of people disable them so it no longer activated the light and buzzer. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76547-low-air-buzzer-going-off-all-the-time/#findComment-594148 Share on other sites More sharing options...
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