Component Tests and General Diagnostics

If the heater outlet air temperature cannot be adjusted with the temperature control knob on the heater-A/C control panel, the following could require service:

- A faulty heater-A/C control.
- A faulty blend-air door servo motor.
- A faulty, obstructed or improperly installed blend-air door.
- An obstructed cowl air intake. The engine cooling system.