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 323i Blower Final Stage Fan Resistor May Fail
BMW 323i Problem
Average Mileage: 122,150 mi (47,000 mi - 245,000 mi)
fan doesn't work well, and now it runs even when everything is off, causing battery to discharge
Visitor, 2000 BMW 323i, 110,000 mi
When the car is turned off you can hear the fan running and cutting off by itself.
AC fan worked intermittenly, sometimes would come on at reduced speed & sometimes won't come on at all.
Cant control the fan blower it goes hi and then low even when I adjust it its got a mind of its own.Dealers cost lot of money to fix it, somebody can advise me please.
Visitor, 1999 BMW 323i, 120,000 mi
Blower fail to turn on.
Visitor, 2000 BMW 323i, 186,000 mi
My AC blower would not run consistently. The AC blower would work intermitedly... but mostly not run. The BMW dealer wanted to replace the blower at $1100. I read online about the "Final Stage Unit" being the problem. I told this to the dealer, and they did not agree. TWO years later, I decided to just replace the Final Stage Unit, and then the blower worked with out issue.
Visitor, 1999 BMW 323i, 210,000 mi
Blower will not come on. Sometimes it works when I leave the setting on high. Sometimes it works if I turn off the car and turn it back on again. Today neither worked.
Visitor, 1999 BMW 323i, 245,000 mi
It's freezing cold out and when I try to turn the heat up it doesn't blow any air at all. It works when it feels like it, I hit bump and the blower kicked on but started the car the next day and it doesn't want to blow any heat once again. I'm wondering if it is the blower motor "resistor"?
Visitor, 2000 BMW 323i, 81,556 mi
Blows don't work at all I can turn temp up down everything but no blowers
Visitor, 2000 BMW 323i, 100,000 mi
keep changing out FSR.