Parking Brake Light not working

[JoeliusZ28]

hey all,

Wondering if anyone here is familiar with how the parking brake is supposed to trigger the brake light on the dash. Mine was working fine until I disturbed something under the dash while working on something else. I thought it would be an obvious disconnected wire/switch but not the case... it looks like there is a white switch at the top of the pedal assembly that makes contact with the arm when it rotates up. I figure this is all it should need to trigger a light but I also found a plastic black button-switch that has a threaded end on it just dangling near the pedal assembly. Pressing the button doesnt appear to engage the light and I can't find anywhere that it would mount on the pedal assembly. I have no clue what else its purpose would be however. I will take some pictures later tonight but figured I would ask now to see if anyone has a picture/diagram/knowledge.

Thanks!

 

[dyeager535]

Parking brake light is triggered through the switch on the parking brake pedal.

The other switch will be for something like cruise control shutoff, torque converter clutch IIRC, etc.

 

[JoeliusZ28]

I didn't even think about seeing if it would install to any of the other pedals. Cruise shutoff on the clutch makes a lot of sense. I guess im going to have to tear the cluster apart and test for voltage in the bulb then...

 

[dyeager535]

I didn't even think about seeing if it would install to any of the other pedals. Cruise shutoff on the clutch makes a lot of sense. I guess im going to have to tear the cluster apart and test for voltage in the bulb then...

Just make sure the switch is operating correctly. It's been years, but I want to think that on mine at one point, the locating pin on the switch broke off, and the switch rotated so it wasn't making contact with the pedal. Not saying the bulb isn't the culprit, but just make sure the switch is working properly first.

 

[JoeliusZ28]

The threaded plastic did end up being the switch for the clutch pedal like you said. I ended up having to work on a couple other things last night but the switch for the brake pedal is visually intact and connected, although the fuse panel is covering part of it maybe there is something im not seeing.

 

[dyeager535]

yeah, there isn't much too it. I can't remember exactly how it works, I *think* the parking brake pedal hitting the switch provides a ground path for the bulb.

 

[K5wrench]

yeah, there isn't much too it. I can't remember exactly how it works, I *think* the parking brake pedal hitting the switch provides a ground path for the bulb.

The proportioning valve can also illuminate the brake light by grounding the lamp as well.
If you get a rear brake failure the loss of pressure will push the piston in the prop valve to the rear, cutting down flow, and illuminating the dash brake light.
A front failure will do the same but is spring loaded and the light tends to go back off (prop piston resets) after the brake is let up.
Also a button on the prop valve to manually reset a front system failure.
To reset a rear system failure, if bleeding doesn't work, it is easiest to remove the prop valve, remove the brake fail switch, and use a pick to re center the piston.

But your problem is a dash brake light Not working at all when e brake depressed.
Have you checked the connector for the dash panel printed circuit overlay?
To the left of the steering wheel.
Under dash.
Above light switch, behind gauge bezel.
Big long connector pushes into a plastic circuit overlay.
Reach up there and reseat it.

 

[JoeliusZ28]

Thank you. I'll try that next otherwise it must be the bulb coincidentally failing at the same time i was messing with the wires under there.

 

[K5wrench]

Thank you. I'll try that next otherwise it must be the bulb coincidentally failing at the same time i was messing with the wires under there.

Definitely check the bulb first.
But grounding the wire on the ebrake assembly or the wire on the prop valve (inside forwardmost crossmember) should make the light come on.. if the key is in run position as well.

 

[JoeliusZ28]

I recently replaced all the bulbs in the cluster so id be surprised if the bulb went already but its certainly not impossible. I'm waiting for rainy weather to go away so i can dig into this some more.