brake light stays on (1 Viewer)

[tlcrookie]

Aloha,
Details:
'91, 190K miles, don't have any maint manuals, my mech aptitude? - very basic knowledge (just changed front pads on a CAMRY for the very first time!)
Symptoms:
Start in the AM, let iddle for about 20-30 min, recent weather is 10 below. Not sure if this is the cause???
Anyway, red "BRAKE" light on dash stays on for about 30 minutes while driving. After several stop lights and stop and go in AM traffic, light goes away.
What I've done so far:
Checked the back lights to make sure bulbs are working - all are ok.
Checked fluid level - all ok.
No "scratching" or grinding noise when brakes applied - as the CAMRY did which prompted me to learn how to change those pads in the firtst place.

Rookie looking for some help here. Want to make sure my brakes wont fail some day, espcecially since I have this huge a.. bumper the previous owner installed - BAR, RAB, ARB??? Whatever - looks great!
Thanks a bunch.

 

[Scamper]

Welcome to the forum! 10 below in Hawaii?!

There are a lot of posts on this topic, and covered in more detail that I will. Try a search on brake light(s).

The dash brake light can come on for several reasons:
1. Low fluid level in the master cylinder (MC);
2. Sticking float in the MC;
3. Bad wiring or bad float in the MC;
4. E-brake switch is "on";
5. Low brakeline pressure when braking (i.e., faulty MC)

Probably more, but these are the most frequently seen. From the easiest to check, to the more difficult IMO...do these checks when the dash brake light is on:

First, make sure the e-brake is completely disengaged. It's possible that you've left it slightly engaged.

You said you checked and topped off the MC fluid level. Check also that the float is moving freely. With the engine running and the warning light on, pull the MC cap off, and hold it upside down (so the float move all the way to the "top" of the cap). See if movement of the float causes the light to go out. If it does, either the float is/was sticking or you need a new one, or the wiring is bad (see if wiggling the wires affects the light).

Try having someone depress the brake pedal. If the light goes off, you may have a leak or air in the lines, or a faulty MC.

Finally, I'd check the ebrake switch itself. It may be sticking or the wiring damaged/fallen off.

I'm sure others will fill in the things I've omitted or correct/clarify anything I've gotten wrong

Tom

PS: if the fluid level is the cause of your brake light, it's usually so becuase the pads are worn (leading to fluid level drop) and will soon need replacement. Check if so, and replace before you hear the nasty grinding noises...They're really easy to do.

 

[landtank]

I have a 96 so I'm not sure if the 91 is the same, but on a 96 there are only 2 reasons for the brake light.

1. float level switch in the master cylinder
2. hand brake position switch on the e-brake

Either one when triggered will supply ground to the circuit and turn on the light.

you've do the basics as far as fluid level for the float switch, so now confirm that the hand brake is down. If both these don't shut off the light then troubleshooting is pretty basic. Unplug one switch at a time to see which one is turning the light on. Once you know which circuit it is then dive in to the possible causes.

We've seen the float switch give people problems, alot of the time you might see a dim light and not fully on. This has been a compromised switch and replacing the cap assembly has been to repair.

 

[Seminole]

I've got a 91 and had the same thing happen. A new MC res. cap is usually the culprit. Check the ebrake 1st. If the handle is even a bit loose, it makes contact with the switch and lights it up, even intermittently. Adjust the handle to tighten up if that doesn't fix it, it is probably the cap. If you cruise control is not working, this is why (usually). Also, be sure to check your pads and for leaks like the others have said, just to be safe.

 

[Asiarider]

I bet it is still the brake fluid level. Sometimes it seems okay but the sensor is very sensitive. That would explain the situation that the light will go off after some time.

Mike

 

[tlcrookie]

brake light stays on - Problem solved!

I want to thank everyone for the help.
Solution:
Does this make sense? I was checking the fluid during the day, with the cruiser warmed up and after traveling some miles.
This AM, after checking the reponses, I checked the level - WAY LOW! Filled it up and now I'm good to go.
Does the extreme temp changes affect the level that much? This AM it was -7 F.
Thanks again folks, looking forward to this forum.

 

[landtank]

I'd flush the system if you are seeing that kind of change. Brake fluid seems to be suseptable to moisture.

 

[Wayne]

I haven't experienced this problem on the Cruiser, but I had the identical problem on a Jap built car I once owned....... it only occured during cold weather....... and it too was the fluid level causing the light to come on. Once the engine room warmed up, the light would go out. I just made sure the fluid level was just a little over maximum, and it cured it.

Wayne S

 

[Owyhee Jackass]

How do you access the switch on the e-brake handle?