i've had my 83 533i for a little while now, ac worked great until today.

when i turn the dial to turn up the speed of the blower it doesn't turn on... NOTHING ac doesn't turn on, heater doesn't turn on, nothing. pressed the ac button, nothing works. ALSO the aux fan stopped working, thus the car starts to over heat, this all seems tied together because when i use to turn on the ac the aux fan would turn on, but now it doesn't turn on AT ALL.

Should i replace the aux fan resistor... would this cause this? the aux fan isn't seized or anything it turns when i spin it with my hand, i'm gonna test to see if it even works by hot wiring it in the morning. any help to point me in the right direction would be great.

check your fuses

checked em... they're good

hey i got a 79 bmw and was having the same problem. i dindt think much of it it turned out to be a leak in the water hose that goes from the motor to the heater. found out when the small leak completly blew lol.