1995 Caprice. What can cause the dash brake light to be on?

The dash light in my 95 Caprice is on.

I've checked

Brake fluid level
Switch functionality on the e-brake foot pedal
Beat the side of the proportioning valve with a hammer thinking maybe it's the switch in there?

What else can cause that light to be on? The last thing to do is some full foot pedal hard skidding stops, but I'd like to have a set of brake lines in-hand before I do. I think I'd blow one in the process; there are a couple compression fittings added by a previous owner that I really don't like and need to get rid of.

There are a couple of different lights, which one is it? It might be an electrical open. Check the switches for continuity when they are supposed to be closed, and for interruption when they are supposed to be open.

It's the BRAKE (!) light in the dash. Lower right hand corner.

I know it is a brake light, you stated that, but there are two of them. I do not know which one that one is. The low brake fluid, or the antilock. You still must check all of the switches for operation, and check the grounds as well.

Start checking your switches for proper operation. Check the grounds as well. Most will ground the switch, so when it closes, it shows a fault. You need a VOM.

If the proportioning valve is the cause, I have a couple on hand. My proportioning valve did not cause a brake code when it failed.

If you check your antilock brakes by slamming on the brakes, you will feel them working. If they are not working, you can check them further.

Only two things turn on that light.

1. The parking brake.
2. A pressure differential between the front and rear circuits. AKA: a leak.

Troubleshooting:
1. Pull the parking brake release and lift up the park pedal at the same time. Light out? Parking brake is sagging. Light still on? Your problem is #2.
2. No leaks? Don't just look for puddles on the ground. ALL lines and connections inspected carefully? The long line under the driver's door? No leaks, no rust, no slightly damp looking lines? Pull the rear tires and the drums. Dry? If yes, look closely around the wheel cylinders. Dry? Now pry back the rubber seal that the pistons come out of. Dry in there? Should be. By now, you've found the problem...

Get back to us.

SO this may sound like abuse, but I had a similar issue on my '96 Roadmaster after replacing the front brakes on my wagon and Googled about it. On one of the Impala SS groups there was a thread about the light sticking on. It stated that the proper way to turn off off the brake warning light is to apply 450PSI of force to the brake pedal (basically stand on it and apply as much pressure as you can). That sounded a bit extreme, but I'd tried everything else. Took the car out and ran it up to about 30 mph, jammed on brakes, light went off, but then came back on when I took off. Decided to try one more time, maybe I didn't hit 'em hard enough. Ran it to about 35mph and then slammed the pedal HARD, and the light went off...and has been off since!

Good Luck and hope that does it for you!

-Mike

What 81X11 did was to recenter the switch in the front/rear pressure differential sensor, which sometimes works. jayoldschool has a good troubleshooting guide, but you might want to check the differential switch with a meter to see if it is really actuated first.

This is the original poster; forgot password and it recovered through an old work email I don’t use anymore. Ugh.

Cramming on the binders on a dirt road at 40 made the light go out.