Own a 2003 530I with 68K . Yesterday driving over bridge and had my seat heater on set at level2. Then experienced a terrible order. My back left side began to really burn and when I looked down smoke was coming from the seat. Really in a panic as there was no where to pull off I switched it off and pulled off the road after the bridge. Two half dollar size holes in seat back and black residue on seat. Melted a hole in my pullover sweatshirt and left a sore spot on my back. Called BMW helpline and talked with customer service. I was told they had never heard of such an instance and had no recalls or safety bulletins issued. Told to drive to nearest dealer and they would evaluate , however, no promises from BMW.