I have a 2004 M3 convertible with 59k miles. Last night, while stopped at a red light, the car completely died. Everything! No lights, no hazard flashers, nothing. Luckily, I was alone in the left turn lane and nobody was behind me. After about 15-20 seconds of shock and desperation, I decided to push the car onto the shoulder and out of traffic. After rolling about 5 feet, the car suddenly lit up like a Christmas tree. I hopped in and cranked it up. During the drive home, I noticed that some things on the dash had been reset to zero or null values: clock and trip odometer. This is similar to what happens when the battery is disconnected but how can that happen when the car had been running normally and how could it just suddenly correct itself like that? If not a battery connection issue then what else could possibly cause such bizarre behavior? The only electrical activity (other than fan, lights and radio) that took place at the moment of failure was that I rolled the windows down as I came to a stop. At that point - nothing! Does anyone have any thoughts about this?
Has your car ever been in an accident? The battery cable is designed to sever itself in such a case and sometimes body shops do not replace the end of it and instead just jam it back in. Just a WAG, but you could always wiggle the positive battery cable to see what happens (I'd leave the key out with the parking lights on so you can easily see any effect.)
Thanks, Paul ... no, the car has never been wrecked but, on your suggestion, I did check the battery connections ... sure enough, the positive terminal was not tight ... not loose, mind you, just not really secure ... I could feel and see a slight movement when I jiggled the cable ... I tightened it, but am still leery ... the connection, although not tight, did not seem loose enough to cause a complete loss of electrical current at the moment of total failure the other night ... no one else has responded to my original post so it must be a fairly unique issue and I have no choice but to drive the car ... I'll keep my fingers crossed ... thanks for your feedback and I hope the steps taken from your suggestion make this gremlin go away! Bill.
