98 740iL - Brake lights warning issue...

My brake lights are working fine but the brake lights warning comes on... Is it something wrong with my electrical wiring stuff? Anyone knows anything about this?

Try this - it is probably the "mustard relay".

http://evansweb.info/articles/2003/0...d-relay-repair

Do the lights in the third (center) light come on too?

Originally Posted by TerryY

Do the lights in the third (center) light come on too?

It doesn't come on. What does it suppose to mean?

The brake warning is likely trying to tell you your CHMSL (Center High Mounted Stop Light), aka the third brake light bulb, is out. Replace it and the error may go away.

Also, corrosion of the connections of the bulb sockets/holders can cause a false error message (all if the lights are illuminating).

Did you have any luck?

jake

Originally Posted by crewdog843

Did you have any luck?

jake

Oh I'm outta town for a week so I haven't tried yet, but I'll let you know when I do.

Originally Posted by NC BMW Driver

Try this - it is probably the "mustard relay".

http://evansweb.info/articles/2003/0...d-relay-repair

Where exactly is this fuse box located at?

The Mustard relay was an early E32 problem. Your E38 has a far more advanced light control system.

Originally Posted by TerryY

The Mustard relay was an early E32 problem. Your E38 has a far more advanced light control system.

So where is this fuse box located at?

Two places:
Under the hood, passenger (US) side near base of windshield.
Trunk by the battery behind black felt-like insulation.

Originally Posted by M.Wong

Two places:
Under the hood, passenger (US) side near base of windshield.
Trunk by the battery behind black felt-like insulation.

All my fuses are good so I don't get why it's showing to check the brake lights?

Originally Posted by TerryY

Do the lights in the third (center) light come on too?

Originally Posted by nuttybgc

It doesn't come on. What does it suppose to mean?

Wait, do all three brake lights illuminate on the back of your car when the brake pedal is depressed? If not, that is your first issue. The "check brake light" warning on your dash will trigger if all three are not working.

Do none of them come on? If that is the case, you may have a pedal switch issue, or something more complex within the electrical system.

Do just the two (left and right), or just the third (center) come on? If that is the case, have you changed the bulbs? People have reported that aftermarket bulbs are more likely to cause the "check brake light" error due to resistance or impedence (or something?), but others have not had the same concern.

If all three lights work and you get the error message, you could have corrosion at the sockets and the light housings themselves. People have replaced their sockets, or even their tail lights, if cleaning the conctact points didn't work.

Originally Posted by M.Wong

Wait, do all three brake lights illuminate on the back of your car when the brake pedal is depressed? If not, that is your first issue. The "check brake light" warning on your dash will trigger if all three are not working.

Do none of them come on? If that is the case, you may have a pedal switch issue, or something more complex within the electrical system.

Do just the two (left and right), or just the third (center) come on? If that is the case, have you changed the bulbs? People have reported that aftermarket bulbs are more likely to cause the "check brake light" error due to resistance or impedence (or something?), but others have not had the same concern.

If all three lights work and you get the error message, you could have corrosion at the sockets and the light housings themselves. People have replaced their sockets, or even their tail lights, if cleaning the conctact points didn't work.

Well, when the break pedal is depressed the middle and the bottom right lights don't come on and only the bottom left light illuminates on both the taillights.

Originally Posted by nuttybgc

Well, when the break pedal is depressed the middle and the bottom right lights don't come on and only the bottom left light illuminates.

Well its probably just burnt out bulbs then. If you want to make sure so you dont waste your time going to the store (and 2$) take the bulb out of the working light (since you know that bulb is good) and put it in the center light socket, check if it works, then in the right socket and check. If it works in those 2 then you just need 2 new bulbs. If it doesnt then you have other problems (bad socket...no power to the socket ect)

Originally Posted by M.Wong

Wait, do all three brake lights illuminate on the back of your car when the brake pedal is depressed? If not, that is your first issue. The "check brake light" warning on your dash will trigger if all three are not working.

Do none of them come on? If that is the case, you may have a pedal switch issue, or something more complex within the electrical system.

Do just the two (left and right), or just the third (center) come on? If that is the case, have you changed the bulbs? People have reported that aftermarket bulbs are more likely to cause the "check brake light" error due to resistance or impedence (or something?), but others have not had the same concern.

If all three lights work and you get the error message, you could have corrosion at the sockets and the light housings themselves. People have replaced their sockets, or even their tail lights, if cleaning the conctact points didn't work.

So are you saying when the brake pedal is depressed the center light suppose to come on too? Because mine doesn't but when I turn the headlights on that center one illuminates...

hello!! i have a problem with my break light on my bmw 740 il , when ever i start the car the break light come's on in the back even driving !! can anyone help me with this please

The brake light switch mounted at the brake pedal is your problem. It is either broken or needs adjustment if the brake lights are always on.

You've gotten a lot of good advice, pointing you in the right direction. I will add to the discussion by saying that if you have at least one light working, you probably don't have any major issues to consider. Sounds like you have a combination of small occurences. Pull all bulbs and compare the internal elements (filament) to the known good bulb. If any don't match the known good one, replace it. Most of the time, the high mount (third brake light) bulb is blown.

The other problem sounds like you may have corroded or contorted prongs in the bulb sockets themselves. A very simple fix with a good quality pick, scribe, or any other sturdy but small-tipped tool, and lot of patience and eye for detail should do the trick.

To diagnose a little further, take the known good bulb and place in the sockets that are not lighting up. Upon depressing the brake pedal, if the known good bulb does not illuminate, then you know that socket needs repair or worse case scenario, replacing.

Hope this helps.

Originally Posted by nuttybgc

My brake lights are working fine but the brake lights warning comes on... Is it something wrong with my electrical wiring stuff? Anyone knows anything about this?

I too have gotten the same warning. I was thinking it was just cause it rained.

Hello. My 1998 BMW brake lights on both left and right side will not work. I changed the light bulbs, sockets, and cleaned the place where the socket is inserted. I also checked the fuses. Please help.

Wiring problems for cwbilb2407. Check with volt meter.