M923A2 Question about Parking Brake!!!

[VF4 Smith]

The buzzer for my parking break wont shut off even when I disengage the parking break. Wondering your thoughts on where to start chasing this down? So even when im driving im listening to that horrible buzzer going off.

 

[TwistedOaks]

Are you sure you don't have low air pressure? It's possible the low pressure light is out and you're getting buzzed for that? The buzzer box is under the left side of the dash, just above the fresh air kick vent. I actually put a little electrical tape over the buzzer hole to help the shrillness of the buzzer.

Otherwise, it's the pressure switch near the lever on the floor.

 

[simp5782]

Could be a bad failsafe module as well. More than likely it is just a connection issue.

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[Swamp Donkey]

The buzzer for my parking break wont shut off even when I disengage the parking break. Wondering your thoughts on where to start chasing this down? So even when im driving im listening to that horrible buzzer going off.

Is the warning light blinking with the buzzer, or is it just the buzzer?

 

[VF4 Smith]

Sometimes the warning light stays on and sometimes its off but the buzzer keeps going.

 

[VF4 Smith]

The low air light comes on then goes off ok when proper air pressure is reached.

 

[98G]

When the sensors fail, they fail on. There's 2 of them.

Your air system likely has moisture in it.

 

[VF4 Smith]

Will draining the tanks do it?

 

[jmb6741]

Make sure the spring brake over ride button is out and the arm on the parking brake switch is not sticking when you put the lever down.

 

[98G]

Will draining the tanks do it?

No. Likely you have moisture all through it. I'd start by testing the sensors and isolating which one failed. I'd probably replace both and rebuild or replace the air dryer.

You understand, this is just my best guess. It could very well be a stuck park brake lever thingy, but I'm thinking you'd have figured that out...

 

[therooster2001]

The field maintenance TM has a good troubleshooting procedure to isolate things, but it sounds like the parking brake wiring. If the low air light goes on and off correctly, than the two air sensors work ok, and is controlled by the fail safe, so that seems ok too. The fail safe is pretty easy to test if you have an extra harness. My money is on the brake switch, and most likely the ground. If it turns out it's the fail safe, I have them in the classifieds. A multimeter, 10-15 min following with the TM, and you'll know. Don't overthink it like I do. The TM is methodical and as long as you follow the correct wires, you'll get it.

 

[randygk]

Here is the schematic for the failsafe system. Test your switches, if they perform as they should then wiring or failsafe module is at fault. I redid the ground at the module and was fixed it for a short time. Replaced the module and all is good

 

[Swamp Donkey]

Sometimes the warning light stays on and sometimes its off but the buzzer keeps going.

On a properly operating system, if the buzzer sounds then a warning light should be activated with it. Neither the warning lights nor the buzzer can activate independently of each other. This is controlled from inside the module itself. Pressure switches and the parking brake switch can't cause this symptom, of the buzzer with intermittent warning light, because they would affect both the buzzer and lights. A failing module can also cause a constant buzzer but the other symptom is the key here.

You most likely have a bad failsafe module. A bad ground is a possibility, but it should theoretically affect both the buzzer and warning light too.

 

[VF4 Smith]

Is the ground for the failsafe near the break handle?

 

[randygk]

Failsafe module is grounded right at module with wire from multi conductor plug.

 

[randygk]

Ground for parking brake circuit switch is at parking brake handle base

 

[cselectricsouth]

I am a 1st time 923 owner & just recently The air spring break overide light has come on what is this indicating

 

[Ford Mechanic]

.......

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[Ford Mechanic]

I am a 1st time 923 owner & just recently The air spring break overide light has come on what is this indicating

You pushed in the override valve.

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[Ford Mechanic]

It's the push knob on the dash towards the passenger side.
It should be pulled out.

Disengage air and parking brake with the closest lever to you on the floor between the driver and passenger seat

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