The air temperature valve sensor positions the temperature door according to the setting of the temperature control on the temperature control knob. For the full COLD temperature setting, the temperature control returns approximately 1.0 V to the air temperature valve sensor.

When the temperature setting is changed to full HOT, the temperature door is moved to the warm position. The output rises to about 12 V. For a temperature setting in the mid range, the temperature door positions itself according to the voltage supplied through the temperature control switch. If the motor stalls when the door location is being changed, voltage is withdrawn by the heater controller/heater and air conditioning (A/C) controller after 45 seconds. This action protects the motor.