General Information

There are three mode actuators to control the different modes, defrost valve actuator, inside air valve actuator and mode valve actuator. When the mode switch is toggled, a signal is sent from the heater and A/C control to the different actuators through the control circuits. When the actuators receive the signals, they move into the desired positions.

The defroster valve actuator is a DC stepper motor by design. The stepper motor has four field windings that are controlled by the heater and A/C control. When the heater and A/C control needs to move the stepper motor, it energizes the proper field windings which rotates the armature a fixed amount in the proper direction. This fixed amount is called a step. Battery voltage for the stepper motor is supplied by the heater and A/C control when the ignition is in the ON position, through the battery positive power supply circuit.

The inside air valve actuator is a DC stepper motor by design. The stepper motor has four field windings that are controlled by the heater and A/C control. When the heater and A/C control needs to move the stepper motor, it energizes the proper field windings which rotates the armature a fixed amount in the proper direction. This fixed amount is called a step. Battery voltage for the stepper motor is supplied by the heater and A/C control when the ignition is in the ON position, through the battery positive power supply circuit.

The mode valve actuator is a DC stepper motor by design. The stepper motor has four field windings that are controlled by the heater and A/C control. When the heater and A/C control needs to move the stepper motor, it energizes the proper field windings which rotates the armature a fixed amount in the proper direction. This fixed amount is called a step. Battery voltage for the stepper motor is supplied by the heater and A/C control when the ignition is in the ON position, through the battery positive power supply circuit.

Attached to the stepper motors are small gears. When the stepper motors are installed on the HVAC module, they mesh with a larger gears which is part of an assembly that drives the linkage of the air mix doors.