What is the Heater Blower Motor Resistor?
The heater blower motor resistor is situated underneath the dashboard in the heater/AC compartment. The resistor enables the heater blower motor to change the speed of the fan. Without this part you will not be able to change the speed of the airflow from the blower motor. It is also possible that the heater motor blower may not work at all. If the resistor has gone bad, it is likely that the fan will work only on the highest speed.
Facts to Note:
If no air is coming out of your vents, you may have a problem with the heater blower motor as well as the resistor. Mechanical resistance to the fan (such as when something gets stuck in the fan), can often cause damage to the heater blower motor resistor.
How to Fix:
Examine electrical circuits to verify faulty resistor.
Remove and change the faulty resistor.
The air and heating system in your vehicle is a closed system, so it won’t be examined during servicing and routine upkeep. If you notice any part of the air and heating system behaving bizarrely, however, you should always schedule an inspection. If your fan is stuck on high, you likely have a bad heater blower motor resistor, and should schedule to have it changed.
Common signs indicating you may need to change the Heater Blower Motor Resistor:
Blower motor only operates at 2 speeds instead of 4 speeds.
Blower motor is not functioning (no air from vents).
Importance of this service:
To ensure proper operation of the blower motor, the resistor has to be functioning correctly or else you may end up with either no airflow from the fan or your fan will be stuck on one speed.