NHTSA Complaint #10984961 — 2001 BMW 325XI

I THINK I KNOW WHY THE CAR CATCHES ON FIRE SINCE MINE ALMOST DID AND I TROUBLESHOOT THE PROBLEM. THE ALTERNATOR IS NOT DISCONNECTED FROM THE BATTERY WHEN THE IGNITION KEY IS TURNED OFF AND THE CAR IS PARKED IN THE DRIVEWAY. IF THE ALTERNATOR EVER OVERHEATS FOR ANY REASON (SUCH AS THE COOLING VENT COMES LOOSE), THE PASS TRANSISTOR IN THE BUILT IN REGULATOR OF THE ALTERNATOR BEGINS TO SHORT. SINCE IT IS NEVER DISCONNECTED FROM THE BATTERY (EVEN WITH THE IGNITION KEY REMOVED) THE FIST SYMPTOM APPEARS TO BE A BAD BATTERY AS THE ALTERNATOR KILLS THE BATTERY. ESPECIALLY IF YOU REPLACE THE BATTERY WITH A NEW, FRESH ONE AND CONTINUE TO DRIVE THE CAR THE PASS TRANSISTOR CONTINUES TO SHORT MORE AND MORE (IT CHARGES THE BATTERY MORE AND MORE LEADING TO OVERCHARGING AND POSSIBLE FIRE) AND EVENTUALLY SHORTS SO BAD THAT EVEN WHEN TURNED OFF IT DRAWS SO MUCH CURRENT FROM THE BATTERY THAT IT STARTS TO CATCH FIRE. IF AT THIS POINT YOU DON'T HAPPEN TO BE THERE TO DISCONNECT THE BATTERY IT BECOMES A CASCADED FAILURE AND WILL BECOME AN ENGINE FIRE. I KNOW BECAUSE THIS IS EXACTLY WHAT HAPPENED TO ME. I WAS LUCKY ENOUGH TO CATCH IT AND FIGURED IT OUT BY MEASURING THE RESISTANCE OF THE ALTERNATOR AND WAS SHOCKED AT HOW LOW IT WAS. I REPLACED THE ALTERNATOR AND EVERYTHING HAS BEEN FINE SINCE. I STILL HAVE THE OLD ALTERNATOR IF ANYONE WANTS TO EXAMINE IT. IN MY OPINION THE ALTERNATOR SHOULD NEVER BE LEFT CONNECTED TO THE BATTERY WITH THE IGNITION KEY OFF. I JUST DON'T SEE ANY REASON FOR IT. SINCERELY, [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6). *TR