Parking brake light always on, except when it isn’t

[chevytech87]

Trying to determine if my parking brake switch is the culprit (I frequently use the parking brake and hope the switch is sticking) or if the proportioning valve is causing the light (This would suck because I really, really don’t want to replace that garbage again). With the connector at the parking brake switch unplugged the circuit should be open (light off) if I’m not mistaken? 1987 R1500.

Thanks for the help!

 

[Rusty Nail]

Oil pressure warning light??

Check he oil. Time for a change??

 

[Ricko1966]

Trying to determine if my parking brake switch is the culprit (I frequently use the parking brake and hope the switch is sticking) or if the proportioning valve is causing the light (This would suck because I really, really don’t want to replace that garbage again). With the connector at the parking brake switch unplugged the circuit should be open (light off) if I’m not mistaken? 1987 R1500.

Thanks for the help!

Bleed right front. See if the light goes out,if not bleed right rear see if the light goes out.

 

[Joshua Keith]

My parking brake light was on but very dim, then when I applied the parking break, it would light up. I bled the brakes, didn’t do anything for it. I changed my proportioning valve and it fixed it.

 

[Ricko1966]

Did you bleed them the way I said? There was a reason I made the suggestion I made, the way I made it. If the proportioning valve is not centered, when you equalize the pressure it will recenter its self. You may need to create a low pressure condition on the front to center the valve and turn off the light. Conversely it may be off center the other direction so try one direction if no improvement try the other direction. Your goal isn't to bleed the brakes, it is to center the valve. P.S. this would have to be old school, buddy in the car you cracking bleeder valves.

 

[chevytech87]

Bleed right front. See if the light goes out,if not bleed right rear see if the light goes out.

Will give it a try after work. Does the valve frequently get off center randomly or is this an indicator of a bigger issue? Assuming this is the problem

 

[Juggernaut]

Trying to determine if my parking brake switch is the culprit (I frequently use the parking brake and hope the switch is sticking) or if the proportioning valve is causing the light (This would suck because I really, really don’t want to replace that garbage again). With the connector at the parking brake switch unplugged the circuit should be open (light off) if I’m not mistaken? 1987 R1500.

Thanks for the help!

Yes, if you disconnect the wire to the parking brake switch, the light should go out. The switch grounds out when the brake is applied. If it's still on, it's the proportioning valve. The only time my light came on was from a crushed brake line, but I think other issues can cause it.

 

[Ricko1966]

Will give it a try after work. Does the valve frequently get off center randomly or is this an indicator of a bigger issue? Assuming this is the problem

They get off center by design so if you have unequal pressure the valve go's off center to prevent brake fluid to the low side at the same time triggering the dash light to let you know you have a problem. Just occured to me if front or rear portion of master is bad then the bleed to reset light won't work. Master probably isn't the issue. But... More likely leaky line, hose, or wheel cylinder. Very out of adjustment rear shoes, very warped, or very loose front wheel bearings, that push the caliper pistons back in the bores.