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B1237

DTC B1237 or DTC indicator M: A Short in the Passenger's Air Mix Control Motor Circuit

1. Clear the DTC with the HDS.
2. Operate the climate control system in several modes.
3. Check for DTCs using the HDS or self-diagnostic.

Is DTC B1237 or M indicated?

YES - Go to step 4.

NO - Intermittent failure.

4. Turn the ignition switch OFF.
5. Test the passenger's air mix control motor.

Is the passenger's air mix control motor OK?

YES - Go to step 6.

NO - Replace the passenger's air mix control motor.

6. Disconnect the passenger's air mix control motor 7P connector.
7. Disconnect the climate control unit 30P connector.
8. Check for continuity between body ground and the climate control unit 30P connector No. 5 and No. 23 terminals individually.






Is there continuity?

YES - Repair short to body ground in the wires between the climate control unit and the passenger's air mix control motor.

NO - Go to step 9.

9. Check for continuity between the climate control unit 30P connector terminals as follows.






Is there continuity?

YES - Repair the short in the wires.

NO - Go to step 10.

10. Turn the ignition switch ON (II), and check the same terminals for voltage to body ground.






Is there voltage?

YES - Repair short to power in the wire(s) between the climate control unit and the passenger's air mix control motor. This short may also damage the climate control unit. Repair the short to power before replacing the climate control unit.

NO - Substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit.