Ac/heater fans - BMW 525i 2002

My ac/heater fan stops working from time to time. It may stop for as long as two days. Technicians cannot diagnose this condition. Any help would be appreciated.

There is only one fan (or blower). It works for both the heat and AC. Sounds like a loose connection or a bad ground. Is there and correlation between fan speed and whether or not the fan works?

Thank you for your response. There is no correlation between fan speed and working.

It’s more than likely your final stage resistor-common problem. Here’s a link with some info I found on the location and replacement if you’re a do-it-yourself type.
Good luck.