1995 Regal Brake Light

[jmikef21]

I have a 1995 Buick Regal 3.1 liter with over 250,000 miles. Here is my problem. Occassionally the red brake light does not shut off when I start the car. It seems to be worse after a long drive hour or longer then if I run in a store and come out usually stays on after starting. Normally if I shut it off and start back up and rev the engine it will go out. Can a drop in voltage trigger this light. I am thinking either battery or alternator? I have had battery tested and it tests good. I think I will probably take off alternator and have it tested today. Anyone else have any thoughts or ideas?

Thanks

[richtazz]

the red brake light in your car will come on for 3 reasons.

1. Low brake fluid in master cylinder (or a defective fluid level sensor)

In my opinion given your symptoms, this is the most likely cause. Your fluid level is right at the threshold for tripping the light, and that's why it comes and goes

2. The emergency brake pedal is slightly depressed or the spring that holds it up is weak

This is also a possibility, as the longer you drive, the more the pedal bounces around possibly causing the pedal to drop and trip the light (as if you have the parking brake engaged while driving).

3. Loss of pressure in braking system

This would cause a sinking pedal and since you didn't say it's doing that, I'll assume it's not your issue. If it is, you need to get it fixed ASAP as you are going to lose brakes and possibly cause an accident.

[jmikef21]

The fluid level was my thought too but I have been keeping an eye on it and it is full and not losing any fluid. So I assume bad sensor? Either that or parking brake switch I should be able to unplug it assuming I can get to it and see if that stops the problem. Do you know if you can buy the fluid sensor individually or is it just part of master cylinder?

thanks

[richtazz]

you can buy the switch separately. It's Ac-Delco part # 18012741. Even if you don't have an AC-Delco distributor in your area, it's only $17.04 dealer retail.

[jmikef21]

Well I think I have it fixed. The alternator tested good so I put a new serpentine belt on and it seems to have fixed the problem. I bought a new tensioner as well but I don't think I am going to put it on as long as it keeps running okay.

Thanks for your help