Brake Light Warning on Overhead Panel

[roger1120]

When I first brought the car the red brake light warning signal would stay on even after pushing the reset button. I went around and noticed that one of the brake light bulbs was burnt, so I replaced it and the light went out when reset. Well, the light popped back on again and it won't go out. Checked the bulbs and they're all working. No change in pedal stiffness. What else might it be. I checked the archives and someone mentioned to check the brake sensor connection. Anything else I should check? thanks

[Rich Euro M5]

If your getting a warning lamp on the check panel for brake lights it has nothing to do with the brake pad sensors. The brake pad warning is in the instrument cluster along in the strip of warning lights that includes the alternator, etc.

If all your brake lamps are functional, including the third brake light on the rear hat shelf. You might have the wrong style bulbs. You need bulbs that are specific to Euro cars, they have tin bases vs the typical bulbs with brass bases. It also might be worthwhile to thoroughly clean the insides of the lamp sockets with some 400 grit sand paper.

Rich

[roger1120]

OK, I went home for lunch and believe it or not the light never came on. Is this a situation that I should just live with? Sounds like a problem with the relay to the display.

[Rich Euro M5]

OK, I went home for lunch and believe it or not the light never came on. Is this a situation that I should just live with? Sounds like a problem with the relay to the display.

Intermittent brake light indications on the check panel is indicative of corrosion and/or the wrong type of bulbs. If things are working correctly you should never see the light on the check panel illuminate unless a brake light bulb actually fails. This has been the case on 3 different E28 5ers I've owned, my deceased 533i, the Euro M5, and my '86 535i.

Rich

[Mark 88/M5 Houston]

If you do decide to investigate your intermittent brake warning lamp problem, you want to replace any "brass colored" base lamps with "steel colored" base lamps. Most auto supply stores will have these listed as "European" lamps. All the connections should be cleaned up and dry, I like to use a fine stainless steel welding brush to clean flat surfaces and a wad of scotchbright for "down in" cleaning.

[BRRV]

This problem can drive you crazy!! I replaced both rear light housings with new units a few years ago and darned if I still don't get these warning lights once in a while. I use brand new, correct european style lamps, check grounds, etc. Still happens. What I have found is to make certain you aren't getting any water leakage (if you need to replace your taillight gaskets, since the eventually fail, they are relatively inexpensive) in the trunk panel area anywhere near the sockets. Check your license plate light assemblies, they are famous for water leakage. Make sure there are no leaking areas on the rear panel! Make sure the sockets (a standard Hella item) are in perfect condition, and use a dilectric grease in the bulb contacts. Also, and I think this is key, pull the 'tabs' (metal ears) of the sockets out (away) from the socket base to ensure a good tight fit against the light assembly, and use a dielectric grease on the contacts (just enough to protect it from water or corrosion). Also, if your bulb sockets aren't new, clean them up thoroughly with a rouge cloth or light sandpaper to ensure a good metal to metal contact. If all else fails - replace the bulb, no matter how new it may be. Specific bulbs give the check relay fits, I can't explain why.

[roger1120]

Thanks everyone, I'll check as instructed here.

[GenaroGodoy]

 

Hello probably is too late but for guys like me that like to fix old stuff i had the same problem with my 1991 325ix  and my 1986 535i i develop a test to see what's failing ...

need a cheap tester to check continuity 

[kinetik]

I just wanted to say thank you so much for providing this diagram and trouble shooting steps. 

I was so frustrated with dealing with the check light blinking on my dash on my e24. 

Turns out my relay on my third brake light died. 

I just decided to bypass it. Do i have a check on my third brake light anymore no... the cluster yelling at me was a far worse scenario and my other 2 brake lights still have the check.