Codes 5/33624 and 5/33674

Air mixing damper motor - testing

Fault symptom

Permanent: 53624
Intermittent: 33624

Conditions
Air mixing damper motor: Short circuit +12 V, open circuit, short or internal short circuit in Automatic Climate Control (ACC) control module (diagnostic trouble code 53624-33624 on version 2.01 arises in combination with 53674 - 33674).

Fault symptom

Permanent: 53674
Intermittent: 33674

Conditions
Air mixing damper motor: Short circuit to ground (version 2.01).

Testing
ISAT scan tool command: 27A

Display shows:
Desired position of air distribution damper motor 0% (LO) - 100% (HI).

Important : The desired position of the air distribution damper motor does not mean that the motor moves the damper to different positions, but only that this is being requested by the ACC control module. Visually check that the desired position corresponds to the actual position.







Action
1 Visually check that the motor moves the temperature valve by using the buttons to alternately select HI and LO.
2 If the valve does not move, unplug the ACC control module's 39 pin connector and check the resistance in the stepping motor windings across pins 6 and 7 as well as 8 an 9. Resistance should be about 100 Ohm at 20° C (68° F).
3 If resistance reading is incorrect, unplug the stepping motor connector and measure the resistance directly between the motor windings. If this is incorrect, try with a new stepping motor.
4 If resistance values across the stepping motor windings are correct, check for open circuit between the ACC control module's connector and the stepping motor 10 pin connector 98. Also check for short circuits between the wiring harness and ground.
5 If all electrical measurements indicate normal readings, reinstall the connectors. Erase all diagnostic trouble-codes and restart the system. If the fault is still present, try with a new stepping motor.
6 If the fault is still present, even with a new stepping motor, reinstall the old stepping motor and try with a new ACC control module.