Brake lights come on and stay on as soon as cranked.

[NotplayN]

Im guessing its the brake light switch but was curious if something else maybe causing it. I called the BMW dealer and parts dept does not stock it so thats usually an indicator that its not a common problem. However I have had to replace the brake light switch on my ML500 many times... Thanks.

[David.X5]

Sounds like the switch to me, too. You could unplug it from the harness and see if your problem goes away. Jumper the connector to test on and off. Just a simple on/off switch...

[Qsilver7]

Originally Posted by NotplayN

Im guessing its the brake light switch but was curious if something else maybe causing it. I called the BMW dealer and parts dept does not stock it so thats usually an indicator that its not a common problem. However I have had to replace the brake light switch on my ML500 many times... Thanks.

You give no model/model year/build date. Pre facelift & facelift rear tail lights are slightly different. Is there only 1 brake light bulb illuminated in each rear tail light...or do you have more than one bulb illuminated in each tail light? How about the 3rd (high mount) brake light...is it continuously illuminating, too? Do you have any warning lights on as well? If you do, is it only 1...or is it more than one warning light illuminated?

[NotplayN]

2001 BMW X5 3.0 I dont know the build date, vehicle is at my work. I dont know what qualifies it as a facelift vehicle or not (first bmw for me and bought as a fixer upper). All the brake lights are on (left right and high mount). I dont have any warning lights on the dash other than the airbag light is on. I did notice that after I disconnected the battery the brake light and abs light stayed on but went off with in a few minutes.

I unplugged the brake light switch and the lights are still on. Should they be?

[Qsilver7]

All external lights are controlled by the LCM. Is your battery voltage low (below 11.89v)? Low battery voltage can cause weird electrical gremlins.

Are these original lights or have they been changed with aftermarket? Do you know any history of the vehicle that may have led to an electrical malfunction?

Has the instrument cluster or lcm been changed...check the trip odometer area to see if the tamper dot is illuminated.

[NotplayN]

Yes the voltage is low because the vehicle has been sitting for awhile. They are all original lights. What is the LCM? Is that the same as the BCM Body Control Module?

[Ricky Bobby]

Throw it on a battery charger for a few days -

[Qsilver7]

Originally Posted by NotplayN

...What is the LCM? Is that the same as the BCM Body Control Module?

The LCM is the Light Check Module...it's not the BCM.

Here's a bit of history that explains what this module is and does...starting with its evolution with the e38 7 series as the LM (lamp module):

[NotplayN]

Problem with the brake lights is with the DSC unit.