Brake light on dash

[veltboy618]

My brake light next to the speedo stays on. What could be the problem?

[FATRATMATT]

Could be something as simple as your brake pedal not being in the most upright position. Try holding out the brake handle and with your other hand raise your brake pedal as high as you can. Have you checked your brake fuild level? Sounds simple but sometimes forgotten. Do you have power brakes? Could be your brake boaster has a leak. Mine used to hiss until you pressed on the brakes then the hiss would stop. Good luck with it.

[cts-v]

Could be something as dangerous as your master cylinder starting to fail. Mine did about 13 years ago, and I had no brakes driving around a college campus... ended up hopping the curb and driving on the bike path and running a red light and getting pulled over by the cops (who saw me driving on the bike path and running the red light). Thankfully I didn't hit anything or anyone.

Unless it is as simple as the parking brake pedal sagging, I'd certainly suggest investigating the entire hydraulic system until you find the root cause of the problem.

Possible problema areas....
-master cylinder (leaks / air in system / internal malfunction- root cause of my problem)
-brake lines (leaks)
-distribution block (leaks / blockages)
-caliper or wheel cylinders (leaks)
-pedal stroke to the master cylinder

Good luck. There may be other potential issues, these are just the ones I could think of.

[Bluevista]

If the brakes are good and the light is just on it may be the switch piston in the distribution block/valve is out of center and hanging up/bad or something else on the electrical side is grounding out. The parking brake switch sounds like a good one to check first.

[joe_padavano]

Originally Posted by cts-v

Could be something as dangerous as your master cylinder starting to fail.

While I'm glad you weren't hurt in that episode, the reality is that the BRAKE light on the dash comes on for one of two reasons.

First is whenever the E-brake is activated. There is a switch on the E-brake pedal frame that makes contact whenever the pedal is moved at all. If the pedal is not fully up (or if the brake cable is not properly adjusted) the light will come on.

Second is if the differential pressure valve in the distribution block (or combination valve on 1971-up cars) has been triggered. This valve is a piston that is located between the front and rear brake circuits in the distribution block. If pressure is lost in one of the circuits, the pressure in the other side pushes the valve, which in turn operates a switch that illuminates the light. A weak master cylinder will usually not cause the light to illuminate; it would require a loss of fluid in one of the circuits. If the master cylinder is not low on fluid, then it is very likely that the problem is simply the E-brake switch. If fluid is low, then find and correct the problem and bleed the brakes.

Note that there is a third possibility. Both the E-brake switch and the differential pressure switch illuminate the light by completing the ground side of the circuit (the other side of the bulb gets constant +12v when the key is on). If either of these wires has inadvertently grounded out, the light will come on.

[GoodOldsGuyDougie]

where is the parking brake switch? I have the same Problem and the Brake system is all new, but the Parking Brake is not Hooked up.

[rocwal]

switch should be on the side of the foot pedal bracket frame, when pedal is pushed down the switch activates the light in dash.
rocwal
Dan B

[Lady72nRob71]

Originally Posted by GoodOldsGuyDougie

where is the parking brake switch? I have the same Problem and the Brake system is all new, but the Parking BARKE is not Hooked up.

See this thread, post #4...
http://classicoldsmobile.com/forums/...s-staying.html
It shows the switch location on a '72 Cutlass... What year is yours?

[cts-v]

I just want to reiterate the point of my earlier story (about losing my brakes). It seems to be very common for the parking brake pedal to sag. It happened fairly often on my car years ago. As a result I got used to seeing the dash light come on occasionally, so I wasn't too alarmed when I saw it. If the sagging parking brake pedal is not the problem, and the switch itself hasn't failed, then something else in the hydraulic system is causing the light to come on, and should be addressed. Good luck, and let us know what you find out.

[GoodOldsGuyDougie]

Lady72nRob71 Thanks for the Help, as always it is appreciated.