I have a 2002 325i that, when cold, the heater/ac fan speed fluctuates faster-slower-faster-slower, etc. Once the car warms up, the fan speed settles in to whatever speed is called-for by the computer and the problem goes away. That is, until the next time I start the car from "cold". I've heard of this happening with others but didn't pay much attention to how to fix. Any know how to fix? Thanks.