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.Google+
Car Problem Reports
BMW 325i Blower Final Stage Fan Resistor May Fail
BMW 325i Problem
Average Mileage: 102,466 mi (35,000 mi - 190,000 mi)
Visitor, 2001 BMW 325i, 80,000 mi
Fan was intermittent. Dealer told me my blower resistor (final stage unit) has gone bad and the repair would cost $350. Didn't have the dealer perform that repair. Bough part online for $65 and found DIY online. Took 45 mins.
Visitor, 2002 BMW 325i, 67,345 mi
Blower motor keeps running after you turn car off and running. Battery. Down
Visitor, 1993 BMW 325i, 189,000 mi
The heater blower does not work and blows cold air continually. I replaced the resistor back about a year ago. Do you have any suggestions for this.
AC/Heater blower will not work
Visitor, 2003 BMW 325i, 130,000 mi
Air conditioner/heater hisses as if it's coming on, but blows no air now in either mode. Is this an easy, inexpensive fix?
The blower speed varies up and down while driving with the AC on. Sometimes the blower will fail to operate at all. I have not had it repaired yet.
Visitor, 2001 BMW 325i, 172,300 mi
Blower fan resistor failed. When I switch on my AC the speed does not increase or decrease. A local technician got a new blower resistor and replaced it for
Visitor, 2001 BMW 325i, 120,000 mi
Blowwer final stage resistor failed. Fairly easy to replace not an expensive part. Problem was I could not control fan speed.
Visitor, 2001 BMW 325i, 122,532 mi
heater will work but my car warms up and i turn off the engine then turn it back on it doesn;t work at all
Visitor, 2003 BMW 325i, 35,000 mi
variable blowing, sometimes not at all, then finally just stopped working altogether. $500 for part and labor at a BMW dealer