Flashing parking brake light.

[MGregoir]

When I am driving, my parking brake light intermittently flashes. This has been happening occasionally, and I first noticed it about a year ago when the car would say go under an underpass and the suspension would compress at the bottom. The parking brake and ABS light would both flash on at the same time.

The factory service manual (it's a 1999 Malibu) doesn't list anything in troubleshooting for the parking brake indicator coming on with the brake not being set, so does anyone have an idea what it may be? Bad electrical supply, bad connector, bad wheel speed sensor, short to ground? I have to get an ABS compatible code reader here shortly anyways, but I am wondering if it may be something simple I am just missing that might be as easy as solder and heat shrink.

 

[GMGuy]

A few possibilities; don't know if it specically applies to the Malibu;

Brake fluid up to level? If the level is low (on some cars) it will cause the brake light to light.

Find the location of the parking brake switch, is it still securely mounted? Does the lever move at all when you hit bumps? If it does it may be moving just enough for the switch turn on.

Loose ABS sensor connector/Broken wire that jouncing the car will cause a make/break in the connection.

Alex.

 

[MGregoir]

The thing that throws me off is both the ABS and parking brake light come on simultaneously.

The brake fluid level is up.

The parking brake lever is tight and functional, and the light goes on when I set the brake and switches off as soon as I disengage it.

I think I ate yet more wheel speed sensor wiring on one of the rear wheels.

 

[jldcol]

The ABS system has a seperate power feed, but do the 2 lights your talking about share the same circuit/power supply?

 

[mechtech2]

Like you surmised, dive into the sensors.
Rust, dirt, or faulty wiring or connectors have to be made right -no matter if they are the whole problem or not.

 

[eljefino]

Scan the ABS, it'll remember.

Traditionally the "brake" light was for low reserve fluid, but they may have wired it to come on with ABS faults as well as an attention getter. It would seem like this with you sloshing fluid around but you say it's full...

I blew a line (in my driveway!!!) once and while both lights came on, they were at separate levels of out-of-fluid.

Your manual should have a bold type warning for what the "brake" light means, usually in "trouble on the road" chapter.

 

[artificialist]

Originally Posted By: MGregoir
The thing that throws me off is both the ABS and parking brake light come on simultaneously.

The brake fluid level is up.

The parking brake lever is tight and functional, and the light goes on when I set the brake and switches off as soon as I disengage it.

I think I ate yet more wheel speed sensor wiring on one of the rear wheels.

The regular brake warning light comes on when there is a hydraulic problem, and if the hydraulics have a problem, there is nothing the ABS system can do to control braking. That is why in some cars, the lights appear at the same time.

In short, find the hydraulic problem first. Then the ABS light might not be a problem again. If the light is still on, THEN it is the time to use the scanner and get error codes from the ABS system.

 

[eljefino]

ah, but there is no memory for the regular brake hydraulics warning light. Should be a code... low fluid? for the ABS warning.

 

[MGregoir]

The fluid was halfway between min and max, I topped it up to max and pumped the brakes.

There are two shared ground connections for the low fluid level sensor and the ABS module, one is tight but I have to get underneath the car to check the other.