BMW E32 heater blower faults
E32 blower works only at full power or not at all. What is wrong?
The most common cause is either the blower series resistor (a speed controller, also called the "sword") or worn bearings in the blower motor. It is worth finding out which one is in bad shape by trying them, and replacing that part.
Where is the E32 blower series resistor?
The series resistor is in the front passenger footwell, once the side trim of the centre console is opened. Check the condition of the resistor's plug and solder joints first, because the fault is often in them. In cars registered after 1990, the resistor is implemented differently.
What should you check when the E32 blower does not run at any speed?
Check the fuses and the current supply to the switches first, before suspecting the resistor. The control panel connectors and solder joints, as well as the blower switch contacts, may also be oxidised. The blower motor is replaced from the engine bay side by removing the bulkhead covers.