Dash Brake light won't go off.

[Jaimec]

Ok. Been meaning to get to the rear brakes for a while, and did so today. Bought pads and got to work. Found that the previous owner scored the rotors DEEPLY, and got replacement rotors, as well.

The job went *fairly* well, but I didn't realize that there were left and right pads on top, but not a problem. Got it all done, and the problem is, that the (BRAKE) light on my dash is now on, and I cannot get it to go off.

I left the cap off of the brake fluid reservoir while I worked on replacing the pads/rotors. I then fired it up and pumped the brakes (cap off) several times, and felt the pedal get firm. I then placed the cap on the reservoir. Light still on.

Took a test drive, and the brakes felt great; better than ever, actually. But the BRAKE light is still on.

Fluid was never low. In fact, when I pumped the pedal (cap off, with new pads/rotors), some brake fluid overflowed the reservoir. I further removed fluid to bring the level below the 'max' line (I now owe my wife a turkey baster....and thanksgiving's next week). Light still on.

I checked to see if the fluid overflow came into contact with any of the electrical contacts, and checked them. No. Light still on.

I crawled under the back end and had a friend apply and release the parking brake, while I watched the cables and connectors. They seem to be fine.

I have tested the parking break from 30mph, and it stops in a timely manner, and does not pull to one side, or another.

I have gotten down and played with the the pin-switch for the parking brake, and it seems to be ok, though I have no idea whether it's actually working. The connector and wires *seem* ok, as well.

What have I missed?


Jaime

 

[jremington59]

Why did you take the cap off and pump them if you didn't replace the calipers?

 

[swshawaii]

You only say BRAKE light, not ABS light. Since you've ruled out low fluid, sounds like a parking brake or switch issue.

http://www.explorerforum.com/forums/showpost.php?p=2520446&postcount=2

 

[Dave 1955]

Why did you take the cap off and pump them if you didn't replace the calipers?

For when he pushed the pistons in..the fluid needs to go somewhere. I do it all the time when just changing pads.
But I put the cap back on before pumping them up.

 

[2000StreetRod]

"Brake" indicator activation

According to my 2000 wiring diagrams the "BRAKE" indicator will illuminate when the Park Brake Switch is closed (park brake is not fully released), when the Brake Fluid Level Warning Switch is closed (brake fluid level is low), or when the Ignition Switch is in the START position.

It's unlikely that the ignition switch just happened to fail while you were replacing the brake pads and rotors.

According to Rock Auto the replacement brake fluid level warning switch looks like this:

I can't tell from the photo if it has a float that could stick in the low position. If you disconnect the electrical connecter to the fluid level switch and the BRAKE indicator stays lit then you know its because of the Park Brake Switch.

Since you didn't mention replacing the parking brake shoes I assume you didn't and therefore did not rotate the adjuster screw. Replacing the pads and rotors should not affect the parking brake.

 

[Jaimec]

According to my 2000 wiring diagrams the "BRAKE" indicator will illuminate when the Park Brake Switch is closed (park brake is not fully released), when the Brake Fluid Level Warning Switch is closed (brake fluid level is low), or when the Ignition Switch is in the START position.

It's unlikely that the ignition switch just happened to fail while you were replacing the brake pads and rotors.

According to Rock Auto the replacement brake fluid level warning switch looks like this:
View attachment 76370
I can't tell from the photo if it has a float that could stick in the low position. If you disconnect the electrical connecter to the fluid level switch and the BRAKE indicator stays lit then you know its because of the Park Brake Switch.

Since you didn't mention replacing the parking brake shoes I assume you didn't and therefore did not rotate the adjuster screw. Replacing the pads and rotors should not affect the parking brake.

No, I didn't mess with the parking brake shoes. I did remove the electrical connector to see if it was wet (brake fluid overflowed when I compressed the calipers), and connector was dry. Didn't check the light while it was disconnected, though. I'll try that. I'm inclined to believe that it's the parking brake switch, though, as it's a pretty crappy looking piece of hardware.

Jaime

 

[koda2000]

my guess is it's something to do with the low fluid light/switch. did you just push the crappy old brake fluid and dirt back into the system when you pushed the caliper pistons in, or did you open the caliper bleeders and drain the excess fluid out that way? the reason the the latter method is the way to do it is that you don't want to get all the crap into your ABS pump.

the low brake fluid switch must somehow be attached to a float (although it could be light sensitive/optical, but i doubt it.). maybe forcing the float up to far disconnected/broke it. that switch must be attached to the master cylinder reservoir somewhere. try unplugging it and see if the light goes out, or you may need to jump the wires to make it go out.

the parking brake switch just makes the ground for the BRAKE light. try unplugging it as well.

 

[1998Exp]

I don't believe there is any physical connection between the float and the sensor. Most of those systems, if not all, have a magnet embedded in the float which you see on top of the fluid. The sensor has a reed switch (or perhaps a Hall switch) operated by a magnetic field. When the float drops below a certain level, the magnetic field around the sensor increases to the point of closing the contacts. I would advise the OP to check if the float is not somehow stuck at the bottom of the reservoir.

Incidentally, I have once encountered a brake warning light turning on when a DRL module failed. In DRL-equipped vehicles the brake warning light connection goes through the DRL module, and a failure there can short the line to ground. If it's a Canadian vehicle or somehow had DRL installed in the US, it's worth checking.

my guess is it's something to do with the low fluid light/switch. did you just push the crappy old brake fluid and dirt back into the system when you pushed the caliper pistons in, or did you open the caliper bleeders and drain the excess fluid out that way? the reason the the latter method is the way to do it is that you don't want to get all the crap into your ABS pump.

the low brake fluid switch must somehow be attached to a float (although it could be light sensitive/optical, but i doubt it.). maybe forcing the float up to far disconnected/broke it. that switch must be attached to the master cylinder reservoir somewhere. try unplugging it and see if the light goes out, or you may need to jump the wires to make it go out.

the parking brake switch just makes the ground for the BRAKE light. try unplugging it as well.

 

[2000StreetRod]

DRL connection

1998Exp, I saw the DRL electrical path in the wiring diagrams but didn't mention it because I didn't know if Jaimec's vehicle had DRL and it would be quite a coincidence if the DRL failed at the same time of the brake pads/rotors replacement. But it is a possibility.

 

[Jaimec]

Thanks guys! As it turns out, the problem went away on it's own! Went out the other day and started it...no light.

Odd.


Jaime