Brake light and buzzer staying on finally fixed

[Hawkdriver]

My brake light and buzzer would stay on with the parking brake released. I found the small micro switch in the parking brake bracket and after testing it found that it wasn't releasing. I had to take the switch apart which is riveted together.

I cleaned the contacts and used small screws to reassemble it. She works good now and the light and buzzer goes out when the brake is released. I still want to try and find a new switch to replace it in case my fix stops working. Thought this might help anyone else has been having this same problem. I didn't even realize that micro switch is on the brake bracket as its really hidden and hard to see. Something worth looking at if your brake light and buzzer won't turn off.

 

[TexAndy]

You're lucky. The far more common cause is the controller box for it (also controls low air warning lights/buzzer).

 

[Hawkdriver]

The control box looks like it had been replaced possibly when someone was chasing this problem when it was still in service. I'm guessing that box isn't cheap.

 

[TexAndy]

I think NOS are around 100 bucks, but I hear that you stand a good chance of getting a bad one out of the box.

But, if you study the way they have to work, there is a way to duplicate the functionality of one alot cheaper with some relays and a buzzer. I drew up a diagram for it awhile back but never put it into practice because it would involve splicing into a few wires on that cannon plug connector. Or at the very least, making some parallel connections with scotchloks. Might do it anyways at some point.

Ideally, you could take a stock one apart and replace what are probably stuck relays. Unfortunately, like many other components on these military trucks, they are potted with impenatrable goop.