Parking brake light problems

[tatakahuna]

My park brake light is on all the time...It's a little brighter when the emergency brake is engaged but stays on when disengaged...I put in a new switch and it didn't fix it...My C10 is a 86, I don't think there's any ABS involved...Checked the wheel cylinders and the master; no leaks and power brakes work just fine...Need a wiring diagram for that switch to see if something else is keeping the light from going out when it's suppose to...

 

[MrMarty51]

Must be picking up a ground somewhares,unless they might be a diode in there somewheres,gone bad,causing feedback.

 

[tatakahuna]

Must be picking up a ground somewhares,unless they might be a diode in there somewheres,gone bad,causing feedback.

Thanks

 

[89Suburban]

Tan wire with white stripe. One runs to P-brake switch, the other to the proportioning valve. You could unplug the prop valve and see if the light goes out.

 

[MrMarty51]

Tan wire with white stripe. One runs to P-brake switch, the other to the proportioning valve. You could unplug the prop valve and see if the light goes out.

I furgut about that thing.

 

[RetroC10Sport]

Yep, that was the same problem with my 1981, finally had enough and unplugged the prop valve and it went off.

 

[tatakahuna]

Prop valve

Tan wire with white stripe. One runs to P-brake switch, the other to the proportioning valve. You could unplug the prop valve and see if the light goes out.

Where is that prop valve located?

 

[RetroC10Sport]

Front crossmember just below the radiator on the driver's side, next to the steering box as I recall. Follow the brake lines down to it and you'll find it, it's a small metal box looking thing with brake lines coming out of it and one electrical plug.

 

[MrMarty51]

If one end or the other of the brakes needs bleeding,or the rears adjustment required,it causes an imbalance within the valve and pushes the piston to one side,or the other,and causes the light to come onm.
If the proportional valve/brake light goes off after unplugging it, I then would go looking for the problem.
Most the times it is the rear brakes needing adjusting, if the brake pedal goes most the way to the floor,about two incheds,give or take a little,then the rear brake adjustments is probably the culprit.just sayin.

 

[T-ROD]

I have also had this problem, it wouldnt go off even when the brakes worked fine, I knew it was the p valve switch, but didnt know how or why, I hit the brakes a few times when it was parked pretty hard and it clicked and never came on again, I beleive they get air stuck in them alot, so if its ever ran out of fluid or has been removed, it probably got a bubble or two in the line and turned it on.

 

[tatakahuna]

Prop valve

If one end or the other of the brakes needs bleeding,or the rears adjustment required,it causes an imbalance within the valve and pushes the piston to one side,or the other,and causes the light to come onm.
If the proportional valve/brake light goes off after unplugging it, I then would go looking for the problem.
Most the times it is the rear brakes needing adjusting, if the brake pedal goes most the way to the floor,about two incheds,give or take a little,then the rear brake adjustments is probably the culprit.just sayin.

By disconnecting that wire will I have no rear brake lights when I step on my brake pedal?

 

[RetroC10Sport]

Different circuit altogether. Nothing will happen to the rear brake lights, just the dash brake light should go off.