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.
Car Problem Reports
BMW 525i Blower Final Stage Fan Resistor May Fail
BMW 525i Problem
Average Mileage: 99,833 mi (70,000 mi - 155,555 mi)
Visitor, 2002 BMW 525i, 75,000 mi
the fan sometimes on, sometimes off,and now it's dead not on at all. Is it the only possibility that blower final stage resistor need to be replaced? or there's other possibility like fan motor?
Visitor, 2002 BMW 525i, 128,000 mi
air wouldn't flow so had it insepected and replaced this part.
Visitor, 2003 BMW 525i, 70,000 mi
Final stage resister failure caused fan to continue to draw power after shutting off car. The battery would drain and the alarm would then trigger when set.
Visitor, 2003 BMW 525i
*I coun'nt figure out why cars battery kept on dying and fans blower would come on and not shut off when you needed it to until I replaced the blower final stage unit, all is back to normal, Thank God..........
Visitor, 2003 BMW 525i, 101,779 mi
I have a 2003 bmw 325 i the ac fan wont turn off after my car engine is off
Visitor, 2002 BMW 525i, 80,000 mi
failed in 2008
Visitor, 2003 BMW 525i, 75,000 mi
Blower output varies constantly and sometimes won't turn on. Had to replacew. $300!