BMW Repair: auxiliary fan, bmw x5, material design

Question
My '03 BMW X5 auxiliary fan stopped working properly a few months ago. I first noticed my A/C would only cool when the car was moving, thus giving me the conclusion the aux. fan was not operating correctly. Then, my A/C stopped working at all-not blowing inside. The A/C condensor and motor??? was repaired at a local A /C repair center, but they would not tackle the aux. fan. The a\c does cool a little better, but at the highest fan speed and lowest degrees setting of 60. The MAX speed does not operate at all. What step should I take next to avoid a another huge repair bill? Any suggestion about what the problem might be?
Thanks for your time.
Shelley

Answer
Shelley, you have awful luck it seems. You have two separate issues. By the way good pick on the car cooling at road speed and not at idle. The auxiliary/condenser fan is a bigger job as the bumper needs to come off and the fans aren't cheap. This is first priority. Secondly the Blower motor final stage resistor has failed as ALL E53,E39,& early E46's do. Construction material design flaw. Very simple repair, You can use previous post on E53 final stage replacement to do it yourself if you are handy. Use BMW part 64 11 6 923 204. MSRP on the part is $92.25 You can also look at enthusiast websites to get better instructions with pictures. Should be less than $300 at the dealer.
-Evan