Brake Light Will not go off

[BadQ45t]

Thanks to the help from you guys I've got my 92' Q45 brake light illumination problem fixed by replacment of all 4 bulbs (thanks Daedalus) which had caused the brake fuse to blow.

Right after I replaced the 4 bulbs the car cycled through the diagnostics and than said OK, but when I disengaged the parking brake the brake light didn't go off. I know this light is suppose to go on when there is a problem with the brakes but since it came on right after the bulb replacement and the brakes were just replaced front and rear not 2k miles ago I figure it must a different problem.

Thanks in advance for the help!!

[greg_atlanta]

The parking brake light? Check the brake fluid level.

[natsoundup]

Seems like the issues are independent of each other...

if the bulbs go out...it will say something on your message center...like "stop light inoperative"

I agree with Greg...you could be getting low on fluid... how is your pedal...

take it to someone and have the system bled....you really can't lose getting it done....and it only cost about 35 bucks...

[BadQ45t]

I'll check the fluid tomorrow, thanks. The car is due for a 30k service and I plan to flush everything so I'll include the brakes in that list of flushes.

Thanks!

[shaginator]

If the fluid check, bleeding, etc. doesn't yield a fix for the problem, then it could be the brake sensor that sits with the pads on/near the caliper. It's designed to bust if the pads get too worn, and will thus trigger a warning light to stay on until the sensor is replaced.

[BadQ45t]

I checked the fluid level today and this doesn't look like any brake fluid container I've ever seen. My 80's Z and Maxima had like a little dip stick on the end of the cover, this one didn't have that. I'm going to try to add some fluid once it stops raining and I hope that solves the problem.

Thanks for the hints...I don't think it is that sensor only because my dad just put 4 new brake pads on like 3 months ago and this light just came on.

[DAEDALUS]

That, plus a worn brake sensor on a Q gives a warning in the message window, not in the warning lights. With a bright backlight you should be able to see the fluid level and compare it to the min and max marks on the side of the brake fluid reservoir. Don't let the fluid get low enough to allow any air into the system.

[DAEDALUS]

Related story:

This week I replaced the brake pads on a friend's motorcycle. 13,000 miles and this was his first pad replacement. Keep in mind he's a mechanical engineer. With NO embellishment, here is how the conversation went before I did the work:HIM: I think my brake pads are worn. At one point, my rear brake began to make a grinding noise, so I quit using it and I've been using my front brakes only since then. Now, my front brakes are starting to grind too.ME: When did your rear brake begin grinding?HIM: Oh, maybe about a year ago.ME: WHAT?!! <feeling faint, I reach for a chair to sit on>

So I replaced his pads for him. Get this: His front pads were both worn down to within .010" of the pad's backplate. The rear pads were worse! The rotor had cut a groove maybe .1" into the backplate. The pistons were so close to popping out of the caliper that I had a hard time getting them centered enough to press back in.

[shaginator]

Thanks, Daedalus... I stand corrected.

RE: that motorcycle -- amazing what people learn to get away with. I've seen pics of rotors worn down to the vent ribs.

Below is an example... but there have been worse... yikes.

[Q451990]

I checked the fluid level today and this doesn't look like any brake fluid container I've ever seen. My 80's Z and Maxima had like a little dip stick on the end of the cover, this one didn't have that. I'm going to try to add some fluid once it stops raining and I hope that solves the problem.

Thanks for the hints...I don't think it is that sensor only because my dad just put 4 new brake pads on like 3 months ago and this light just came on.

Never seen one with a dipstick, but I wouldn't doubt it. You can look at the side of the master cylinder... the fluid level should be up to the top line on level ground.

Heath

[BadQ45t]

Well I checked it last night, still a weird reservoir for me but anyhow it was pretty much full. I was able to get a little bit more fluid in there but the light is still on. I guess I'm looking at sensor? My dad told me it happened one other time and that his mechanic "reset" something. I figure he probably topped off the fluid. It was weird how the light came on immediately after I replaced all the brake light bulbs (two were blown, the other two were not looking great). In any case the brakes feel fine so I'm not sure what the deal is...

[Chally]

What light is it?

The master cylinder can activate a light if the float is stuck down.

[DAEDALUS]

I once had the brake system open for about a week when I rebuilt my calipers. When I got it all back together, the brake error light was on. I thought maybe another brake flushing or 2 would fix it, but no dice. I didn't think anything I did could damage any sensors, and I was getting pretty frustrated trying to logically figure out what the problem could be. Then, backing out of my driveway, I stomped down on the brake pedal as hard as I could, and the light went out. Chally's post reminded me of that incident.It won't hurt to give it a shot.

[BadQ45t]

Okay, just to be clear, this is the light that comes on when you have the parking brake engaged.

I'll try the stomping, and Rober thanks for the help with the brake lights, they are working fine.

[Chally]

Disconnect the wires that are at the bottom of the brake reservoir & see if it goes out.

Also check that there isn't a bare wire touching metal at the park light switch. (at the park pedal)

[BadQ45t]

Thanks, I'll check that out tomorrow.

[BadQ45t]

Okay, so putting fluid in didn't change anything, but one post about slamming the brakes really hard was something I tried the other day (also to see if ABS was still working). In any case ABS was indeed still working, and the light went off! It stayed off until I was driving home and going down over a big long hill, when it came back on again. So, any ideas now???

[DAEDALUS]

From what Chally posted, it sounds like the low-fluid sensor is just a float-switch in the fluid reservoir. It may be gummed up a bit, or binding in some other way. Remove the screen in the reservoir (small flat-blade) and baster or bleed the fluid until it's low in the reservoir. Take a peek in there and see if you can see the switch...it's probably near the little harness connector. BTW, did you ever try disconnecting the harness? If that solves turns the light off, it would isolate the issue. I think you're close!

[BadQ45t]

Sounds like a good plan, I'll try that today, thanks again for the help!

[BadQ45t]

Problem fixed, I didn't notice that there was a little plastic stopper that needed to be removed. The level was alittle low, maybe took two gulps out of the brake fluid bottle and the light went off.

I'll have my mechanic do a full flush to figure out if there is a leak at next service.

Thanks much to all!!!

[911/Q45]

That plastic stopper wasn't the float that measures fluid level was it? I don't remember there being anything but a cap and screen on my Q, no stopper.

[BadQ45t]

Well it was a white plastic gizmo that I removed after taking off the cap. I tried to top off the fluid the first time and didn't remove that thing, but when I removed it I could see the fluid down a few "gulps" and then replaced it and the brake light went off.

[DAEDALUS]

That's probably just the screen. It does (should) allow the brake fluid to pass, if slowly. Usually no need to remove it to top off the fluid, but if the screen is clogged, then definitely have the system flushed soon.

[Chally]

Old brake fluid will stain the reservoir making it seem as if there is fluid in it, when in fact it is low.Always take the lid off & check inside if you can't see the fluid move when rocking the vehicle.