Diesel Data: Automotive Repair

Air Mix Control Motor Test

Air Mix Control Motor Test

1. Disconnect the 7P connector from the air mix control motor.

NOTE: Incorrectly applying power and ground to the air mix control motor wilt damage it. Follow the instructions carefully.

2. Connect battery power to the No. 1 terminal of the air mix control motor, and ground the No. 2 terminal; the air mix control motor should run, and stop at Max Hot. If it doesn't, reverse the connections; the air mix control motor should run, and stop at Max Cool.




3. If the air mix control motor does not run in step 2, remove it, then check the air mix control linkage and doors for smooth movement.
- If the linkage and doors move smoothly, replace the air mix control motor.
- If the linkage or doors stick or bind, repair them as needed.
- If the air mix control motor runs smoothly, go to step 4.

4. Measure the resistance between the No. 5 and No. 7 terminals. It should be between 4.2 to 7.8 kOhms.
5. Reconnect the air mix control motor 7P connector, then turn the ignition switch ON (II).
6. Using the backprobe set, measure the voltage between the No. 3 and No. 7 terminals.

Max Cool - about 1 V
Max Hot - about 4 V

7. If either the resistance or voltage reading are not as specified, replace the air mix control motor.