Air Delivery/Temperature Control Circuit

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

When the temperature setting is changed to full HOT, the temperature door is moved to the warm position. The output of the air temperature valve sensor and motor 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 If the motor stalls when the door location is being changed, voltage is withdrawn by the heater controller/heater and A/C controller after 45 seconds. This action protects the motor.