That pesky 'brake light' check light

I know that you're supposed to tap the brake after starting the engine to turn off the brake check light. But why does the darn thing come on again half the time? Any ideas?

When you start the engine, it checks the functionality of the brake light system and if it senses that the brake light hasn't been pressed, the light illuminates. Just put your foot on the brake at startup to eliminate the light illumination.

Now your brake light comes back on after doing this at times?



Mine used to do that when one of my brake lights were out. I couldn't believe it and thought that it was lying to me (like it usually does), but I got out and found one of the bulbs was loose. I cleaned the contacts well and stuck that sucker back in, no problems.

As Botond said, clean the contacts in the bulb sockets, even if the bulbs are working. Also make sure you are running high quality bulbs. Cheapos from the corner auto parts store might not have the same resistance as the original German bulbs. Get some the BMW Dealer and see if it makes a difference.

Good luck

GR

I think I can vouch for the quality bulbs. Currently, I have cheapo bulbs in my rear lights for the turn signals. The brake light bulbs are fine and are the ones that came with the car when I bought it. But, the left-side turn signal bulb sometimes doesn't work in the back and sometimes it does. The contacts aren't very dirty at all, which leads me to believe that the bulbs are just plain cheapo crap. Just last night, I found I had no rear left turn signal because it was blinking extra fast. It was dark, so I pulled into my spot I always park at and turned on the turn signal; nothing was bouncing off the wall as it blinked like a crazed lunatic. But this morning, I turned left and the bulb was fine, blinking like it normally would.

So, in essence, don't buy cheap crappy bulbs.

You can buy good bulbs at the auto parts store. You have to get the european bulbs, not the 1156s.

Does anybody know of decent quality wide angle LED bulbs?

I assume that this is different from the annoying "Brake Circuit Failure" warning. The difference in the USA and Euro lamps is that the USA lamps use the brass base and Euro uses Nickel bases. As others have said make sure you are not using brass, it corrodes and causes the failure.

Yeah, it is different than the brake circuit warning that plagues E32/34/36 cars. Also, the euro bulbs are a different wattage than the other bulbs (21W.) Using the wrong wattage gives the active check control the incorrect resistance, and sometimes it flags it as a bad bulb. Some of the motorcycle parts catalogs have some good LED bulbs, like denniskirk.com

Steve, the brake light switches on E30s have a tendency to fail. If you're getting a brake light failure warning and the lights seem to functioning fine, I'd buy a new switch (they're cheap) and replace it.

The switch is a boxlike little device that's actuated by a plunger at the arm of the brake pedal. look around under the dash and you'll see it. When you get the replacement, just take a pliers and crush the old one -- that's the easiest way to remove it. Then you can pop the new one into place and attach the wiring harness.

I tried some LEDs all across the back--good stuff from www.superbrightleds.com. Blinkers, tails, stops, high-stop, etc. I had to change the flasher relay to compensate for the lower draw of the LEDs (and prevent "hyper-flash")...but I ended up going back to regular incandescent lamps and the stock relay because I couldn't stand the Check panel being incessantly illuminated...and I didn't feel like messing with the car's wiring harnesses to add load resistors...

Forgot that he had a newer E30. They are prone to breakage like all the plastic bodied switches, but I have not had to replace very many. However, if he can get the light to go off and then it comes back on later, it is definitely not the switch, because the car does not know whether or not that switch is even plugged in, unlike the E36 which has a second set of contacts. My bet is corrosion on the contacts of the bulb holder or at least one of the bulbs is not the right type.

I'll try cleaning the contacts and see what happens. If no change I'll cough up some dough for new (Euro) bulbs.

Here's another damn check light that just showed its face--the window washer. It started coming up as soon as I filled the reservoir. Could I have splashed some fluid onto the electrical contacts?

Maybe. Sometimes the float thing just fills with fluid and sinks. You can try twisting it in the tank 180 degrees. If the light goes out then (you have to cycle the key, maybe a couple of times) then the sensor is done for and just leave it like that. You are a big boy and can check your own washer fluid level.

+1 for www.superbrightleds.com. I only use them in the side markers, trunk light, cabin, license plate light (E30), glove box, etc for the same reason. I don't want to mess with the car's wiring and I don't want any fault codes on my check panel.

I put license plate LED lights on my E36 not realizing that check panel also checks that on the E36. So I went back to regular bulbs.

GR

Thanks for the tip. It's not the fluid level that bugs me it's that friggin' blinkin' check light!

Yeah, I've got the dome and trunk lights taken care of, too. However, my E30 checks the license plate lights...which is why I couldn't get away with those...is this a model year difference?

And Steve, the blinkin' check light is SOOOOOO annoying!!! Especially at night...

To get rid of the blinking check light, push in the Check button on your overhead check panel. It will get rid of your flashing Check light on your instrument cluster.

I put in the Sylvania Osram Silverstar bulbs for my headlights and they're way superior to the Hellas I had in there. Night and day you might say...(sorry).

I guess it is model year specific. My 84 doesn't have a check panel. Oh S*$# I just realized I don't know if my M3 checks the license plate lights or not. I have had the LEDs in my 84 for a couple years now and I just bought LEDs for my M3 and have not put them in yet. So, I will have to check before I put them in. If it does check it, then I won't put them in.

I do know the check panel on my M3 does not check oil level like it does on the M20 powered cars.

Botond is correct, once you get a fault, just push the check button to clear it. But it will leave the LED lit in the panel.

GR