You asked how the original BCM failed--it was mainly sporadic window operation (or lack thereof). Window wouldn't go up periodically, Also recently the alarm (which I have never used in 4 years of owning the car) went off 3 times in about 10 minutes of driving. Only did that one other time and hasn't since. Not sure if that is a BCM issue. I couldn't shut it off but it eventually stopped each time.