Blower Final Stage Fan Resistor May Fail on BMW 530i

Problem Description and Possible Solution

The blower final stage fan resistor is known to fail. Symptoms are the heater fan speed varies regardless of the setting, the fan will not turn off when the car is switched off, or the fan will not switch on at all.

Problem Data
RepairPal Verified
Average mileage: 103,766 (35,000–171,000)
6 model years affected: 1994, 2001, 2002, 2003, more2005, 2007
44 people reported this problem
Viewing 1 - 20 of 26 comments
No cool air coming out of vents but you can hear the ac compressor on.

Blower turns on and stays on even when vehicle is switched off. The climate control is also unresponsive.
The Blower final stage fan resistor switch failed...result, fan blower will continue to run and drain the battery after a couple of hours after being parked. Listen for sporadic fan blower cycling well after the engine has been cut off. In addition, note air flow exiting the arm rest center console between seat. The air flow pressure will fluctuate in strength, but is noticeably obvious as a function that should normally be switched off. New fan blower switch repair will easily run you over $450.00. Be careful not to get caught up with having to replace the entire blower...not necessary.
Fan won't blow
I live in Florida-the last few weeks my heater would go on by itself getting hotter as I drive in 90 degree weather. It will remain on even with the car off. Brought it to a repair shop and they could not figure it out. Brought it to a BMW Dealer and they want to keep it a couple of days with the diagnotic check started at minimum 250.00 without repair. That means Im held hostage for the entire Labor Day day weekend. Going to try replacing the resistor if I can locate one and find a mechanic to believe thats what it is. Im a single MOM and most mechanics take me for granted.
Blower runs when car is off.
Blower was acting up, replaced the resistor and it's been working good as new.
Replaced fan assembly.
Cabin fan won't shut off at button nor when car is off
Blower Fan runs loudly and won't shut off when the car shuts off.
Same problem. Bought a new resistor and it works fine now.
Replaced resistor under passenger foot area
A/C blower uneven operation; fan continues to run after ignition turned off; car will not start; no juice.
fan went on during the night while parked. Battery died. Called road service and replaced the battery. One week later new battery died. Took to dealer, replaced with BMW recommended battery. Died one week later. Took to local shop and paid $100.00 to study problem could not find problem. After a few months of this, I walked into the garage at 11PM one night and heard the heater fan running. Took the car to the dealer the next day, explained what I heard, and they replace some part and the problem is now history. The part was activating the blower to run during the nights which over time drained the battery.

My current problem at 170,000 miles is Air Bag is making a knocking noise and cannot find anything in the internet regarding others having this problem.
But problem started long before, I just had no idea until I searched the net.
The blower will not turn off or cool the car
AC/Heater fan does not work