What does a heater resistor do?
reduces the voltage available to the blower motor.
An electric heater is a resistor. It is a resistor with the right amount of resistance to take the required amount of power at the specified voltage. With a case to put it in and louvres to let the warm air circulate, that is a heater. Resistance in ohms is equal to the voltage-squared and divided by the watts.
Fig 15 Blower Motor Resistor NOTE: The blower motor resistor is located on the lower right side of the heater housing. REMOVAL # Remove lower right underpanel silencer/duct. # Disconnect wiring connectors on blower motor resistor. # Remove blower motor resistor retaining screws. # Pull blower motor resistor out of heater housing.
The blower motor resistor is mounted in the heater box directly behind the dash glove box. Remove the contents of the glove box and push in on both sides of the glove box stops. The glove box door will fold down exposing the resistor. Remove the two screws holding the resistor in the heater box to remove the resistor.