Air Brakes - 2 Brake Light Switches, Why?

[Hoof-hearted]

1999 Fleetwood Discovery 34Q, DP 275 Cummins
My brake lights come on randomly while driving or standing still. I found there are 2 brake light switches wired parallel at the brake pedal controller. Anyone know why there would be two? I can only think of one reason for the brake lights to be activated and that would be with the pedal depressed. Although, using the Jake Brake does make them come on also but, there's no activation from the air in the pedal when that happens (I don't think). The switches are $60 ea and I'm cheap. Don't want to replace both if I don't have to.

Any ideas?

Jim

[Cincy Steve]

Jake brake cut-out?

[gpounder]

No clue is this factory but if there was a electric trailer brake then it might have been added.

[twinboat]

There are 2 switches because there are 2 independent brake systems.

Even if one system is drained, the other will still apply the brakes and turn on the brake lights.

Add far as your problem, if you have a floor mounted brake pedal, there is a good chance that its sticking on the hinge pin near the floor. That leaves the brakes slightly applied and activating the switchs.

[asuperheat]

Originally Posted by twinboat

As far as your problem, if you have a floor mounted brake pedal, there is a good chance that its sticking on the hinge pin near the floor. That leaves the brakes slightly applied and activating the switchs.

That would be my guess also. Pull up on the brake peddle when it is happening if the brake lights go out that's probably it. The cruse control would not engage with the lights on so if you find that the cruse wont work while traveling pull back on the brake with your foot. If it then engages it isolates it down to the peddle not returning completely.