Blower/fan does not work for air conditioning or heater on 2003 BMW 325i

The blower/fan does not stay on when I try to use the air conditioning or heater. It came on for an instant and then doesn't work again. Can you tell me what repairs may be needed? Thank you in advance.

Asked by for the 2003 BMW 325i
Just like European Motorsports said, it's a very common problem.
They gave you a good price. Look them up if you are in the area.

It's a relief to know this is a common problem and not too costly to repair. Thank you for your response.
1 more answer , 2 more comments
The blower regulators go bad on these BMWs. We do them a lot. Price is $265.50 plus tax, installed. It takes about an hour and a half to do the work. We can do it while you wait. Call for appt.
Thank you for the information, you were very helpful!
I have a 1994 530i bmw the heater blower stop working about a month ago. I took my car in for a check up the repair guy put what ever was loose back.Now i a having the same problem it sounds like it wants to come on. what could b the problem.