|
Just a heads-up on this: If you make a lot of short trips, a new battery probably won't solve your problem. I have this same problem every winter, and the new battery I had installed this summer did Absolutely Nothing to solve the problem.
The real problem is simple: BMW designed the charging system to focus on fuel economy - Even if the battery is going dead! I am amazed (and angered) every winter that they went to the effort of putting logic into the ECU which limits fan speeds when the battery is low - and when those higher fan speeds are most critical - rather than just telling the alternator to charge more aggressively. The "official" solution is to buy a trickle charger - and apparently leave your hatch open all night long or slam a power cord in the 5th door.
BTW, to the original poster: By turning on the heated seats and steering wheel, you unfortunately made the problem worse. I'm rather surprised that BMW doesn't disable those systems when the battery is low as well. But I understand why you did this. The first time I had this happen, I assumed the fan was broken. Never occurred to me that this sort of behavior would be designed in.
_Jeff
|