Wouldn't want to speak for all cars, but my 1997 Mazda Bravo (aka Ford Courier) seems to have the following setup:
the fan speed is controlled by adding 1 Ohm 1 A resistors wired in series.
eg Fan spd 4 has no resistor, spd 3 = 1 Ohm, spd 2 = 1+1=2 Ohm etc.
(at least 1 amp resistors are required - I used NiCr wire coiled up to allow cooling.)
The resistor pack is screwed onto the top of the blower motor behind the glove compartment.
Cheers
Blower motor resistors are usually located close to the blower motor.
Blower motor resistors are usually located close to the blower motor.
Blower motor resistors are generally found nearby the blower motor.
Blower motor speed resistors are generally located close to the blower motor.
Check the resistance on the blower motor.
There is only one blower motor resistor and it is located in the evaporator housing.
Blower motor speed resistors are generally mounted close by the blower motor. They rely on the blower to cool the resistor.
The blower resistor controls the speeds of the blower motor Hi-resistance lower motor speed Lo-resistance higher motor speed
It is a device with multible resistors that controls the speed of a blower motor.
The resistors for the blower moter are located in the path of the air blown from blower motor
If it has separate blower speed controls for the front and rear, it has separate resistors. Blower speed resistors are mounted close to the blower motor it controls for cooling purposes.
One can purchase a blower motor resistor either in car part shops, like Autozone. Alternatively, one can try looking in eBay for cheaper blower motor resistors.