I have a 1996 328i and I started having some trouble with my climate control unit. Low and behold my mom's 1997 328i started having the same problems at the same time. I did some research and found a web page from Richard Swope about a cheap fix (swapping a capacitor). My mom went to BMW and got it fixed for $500 while I decided to try the DIY route. I had no problem removing the unit and opening it up. I noticed is that there was a hell of alot of dust in there so I cleaned it all out. Then I got to the capacitor swap and I chickened out. So I tried to re-install the unit to see if the cleaning helped and....WOOHOO....it worked!
I wish I could thank Richard for his very helpful web page but there is no email address there. In any case I am very happy and $500 richer.
I know that there are probably a ton of people who have already done this but I had to share with someone.