The need for a blower motor is on any vehicle that has a heater or for that matter even a vehicle that has an air conditioning system. In almost every kind of car, there will be heater motor installed or an AC motor. It works on the inside; its mechanism is what forces air across either an evaporator or a heater core. In order to make sure that the speed of the motor is regulated there is a resistor also working along side the motors. The use of a resistor here is to allow the motor to spin faster. This is used at a time when higher speed is selected for the blower motor fan to work on; in this case, it is the resister that allows it to spin faster. This in turn causes more air to get pushed out.

There are a number of things that you need to keep an eye one when dealing with this kind of machine:

1. Make sure that it is properly oiled. Friction due to lack of oil can cause the motor to burn out.

2. Make sure that the parts, which are exposed to dampness/water, are not catching rust. In such as case the motor should be changes as a rusty motor may snap.

3. Make sure that the resistor is controlling the speed of the motor properly. Speed of the motor need to be kept consistent according to the need of the heater or AC.

4. It should not be used for a longer period than that specified by the manufacturer.

It needs to be monitored and checked over a period of time to make sure that it is in good shape. This is because at some point in time it may wear away; this is a possibility especially if the cabin filter is not changed at desired and specified intervals. The wearing away of a motor is left unchecked can in turn cause several other problems, the resistor would work over time causes it to get damaged or even break. The over all machinery that the blower fan keeps ventilated may get over heated and stop working. Fresh air and pressure is very necessary for the car machinery especially the engine. The lack of proper ventilation can cause it to get over heated and at some point even burn out.