My wife's 03 Cooper (80K miles) has already had the BCM replaced once. The last time it affected the alarm, power windows, and power locks.

This time, she told me that the right turn signal wasn't flashing. She assumed a bulb was out. That problem went away on it's own and then her headlights (low beams) would not work. High beams OK. That also went away on it's own.

This all happened in one morning. By the time she got home that day she said everything was fine, but when I looked at the car parked with the engine off, key removed, and doors locked - one brake light (right) was still on.

I knew that would drain the battery so I disconnected the battery overnight. Reconnected it the next morning, hoping that a "cold reset" might help. It's didn't. The same right brake light was still on, even before I put in the key and started it.

Do the headlights/turn signals/brake lights all go through the same body control module?

 

Bump - no input from the NAM community? Wow, that's a first...

 

I had some issues that were attributed to the BCM, but they didnt include lights. You say the car has 80k miles. Does it have the original battery because my symptoms, although indicative of a bad BCM, turned out to be a weak battery.

Sorry, but thats all Ive got for you.

 

Yes, the BCM controls all of those lights.

I don't know what to recommend. It's unusual that the BCM would go out a second time unless you have a problem like water getting into that area (should have been noticed the first time). Do you happen to have the rear fog mod that makes the top taillight bulb operate as an extra brake light?

 

New battery about a year ago.

Yes, I have the diode-mod in place on both my MINIs. That's the first thing I removed when she started having lighting issues.

 

Was the diode mod ever used with the second BCM, or was it removed only after the latest issues began (in that case, the damage might have already been done). With this mod I recommend using LED bulbs in the top positions to minimize the additional current draw.

 

Diode mod was in place with both BCMs. I removed the diodes when she had the lighting issues - which I know, may be too late.

I also have the diode mod on my car - original BCM, over 160K miles, no issues.

But let's not debate the pros/cons of that mod - at this point I just want to fix the car and move on.

Do you think a new BCM is going to fix this, or is it possible the problem is elsewhere?

 

The BCM is a single point of failure that could cause problems for those different lights at the same time. You could dig through the wiring diagrams to look for other possibilities.

 

I was looking at the wiring diagrams in the Bentley manual. Gave me a headache...

I guess it's BCM replacement then. I just wanted to make sure I was on the right track before ordering a $400 part.

 

In my case, the BCM was getting wet due to a water leak. I managed to save the BCM by removing it and drying it out. The water caused all kinds of funky issues with the lighting (among other things) - so you might want to double check and make sure yours isn't getting wet.

 

If you have a sunroof and the drains are clogged, the water conveniently travels down to behind the fuse panel where it can cause problems with the bcm. Ingenious design.