B1223

DTC Troubleshooting: B1223 or Indicator M

DTC B1223 or DTC indicator M: A Problem in the Rear Blower Motor Circuit

1. Clear the DTC with the HDS.

2. Turn the ignition switch to LOCK (0), and then to ON (II).

3. Do the self-diagnostic function with the HDS Initial Inspection and Diagnostic Overview or climate control unit. Initial Inspection and Diagnostic Overview

4. Check for DTCs.

Is DTC B1223 or M indicated?
YES - Go to step 5.

NO - Intermittent failure, check for loose wires or poor connections on the rear blower motor circuit.


5. Turn the ignition switch to LOCK (0).

6. Check the No. 2 (RR BLOWER) (30 A) fuse in the under-hood fuse box, and the No. 30 (10 A) fuse in the under-dash fuse/relay box.

Are the fuses OK?
YES - Go to step 7.

NO - Replace the fuse(s), and recheck. If fuse(s) blow again, check for a short in the No. 2 (RR BLOWER) (30 A) and No. 30 (10 A) fuse(s) circuit.


7. Connect the rear blower motor 2P connector terminal No. 2 to body ground with a jumper wire.

8. Turn the ignition switch to ON (II).

Does the rear blower motor run at high speed?
YES - Go to step 9.

NO - Go to step 24.






9. Turn the ignition switch to LOCK (0).

10. Disconnect the jumper wire.

11. Disconnect the rear power transistor 4P connector.

12. Check for continuity between the rear power transistor 4P connector terminal No. 2 and body ground.

Is there continuity?
YES - Go to step 13.

NO - Check for an open in the wire between the rear power transistor and body ground. If the wire is OK, check for poor ground at G503.






13. Connect the rear power transistor 4P connector terminals No. 2 and No. 4 with a jumper wire.

14. Turn the ignition switch to ON (II).

Does the rear blower motor run at high speed?
YES - Go to step 15.

NO - Repair open in the ORN wire between the rear power transistor and the rear blower motor.






15. Turn the ignition switch to LOCK (0).

16. Disconnect the jumper wire.

17. Disconnect climate control unit connector B (14P).

18. Check for continuity between body ground and climate control unit connector B (14P) terminals No. 13 and No. 14 individually.

Is there continuity?
YES - Repair short to body ground in the wire(s) between the climate control unit and the rear power transistor.

NO - Go to step 19.






19. Check for continuity between the following terminals of climate control unit connector B (14P) and the rear power transistor 4P connector.





Is there continuity?
YES - Go to step 20.

NO - Repair open in the wire(s) between the climate control unit and the rear power transistor.






20. Turn the ignition switch to ON (II).

21. Measure the voltage between body ground and climate control unit connector B (14P) terminals No. 13 and No. 14 individually.

Is there any voltage?
YES - Repair short to power in the wire(s).

NO - Go to step 22.






22. Reconnect climate control unit connector B (14P).

23. Test the rear power transistor. Rear A/C Power Transistor Test

Is the rear power transistor OK?
YES - Check for loose wires or poor connections at climate control unit connector B (14P) and at the rear power transistor 4P connector. If the connections are good, substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit.

NO - Replace the rear power transistor. Rear A/C Power Transistor Test


24. Disconnect the jumper wire.

25. Disconnect the rear blower motor 2P connector.

26. Measure the voltage between the rear blower motor 2P connector terminal No. 1 and body ground.

Is there battery voltage?
YES - Replace the rear blower motor. Rear Blower Motor Replacement

NO - Go to step 27.






27. Turn the ignition switch to LOCK (0).

28. Remove the rear blower motor relay from the dashboard wire harness, and test it. Power Relay Test

Is the relay OK?
YES - Go to step 29.

NO - Replace the rear blower motor relay.


29. Measure the voltage between the rear blower motor relay 4P socket terminal No. 1 and body ground.

Is there battery voltage?
YES - Go to step 30.

NO - Repair open in the wire between the No. 2 (RR BLOWER) (30 A) in the under-hood fuse box and the rear blower motor relay.






30. Turn the ignition switch to ON (II).

31. Measure the voltage between the rear blower motor relay 4P socket terminal No. 2 and body ground.

Is there battery voltage?
YES - Go to step 32.

NO - Repair open in the wire between the No. 30 (10 A) fuse in the under-dash fuse/relay box and the rear blower motor relay.






32. Turn the ignition switch to LOCK (0).

33. Check for continuity between the rear blower motor relay 4P socket terminal No. 4 and body ground.

Is there continuity?
YES - Repair open in the GRY wire between the rear blower motor relay and the blower motor.

NO - Check for an open in the wire between the rear blower motor relay and body ground. If the wire is OK, check for poor ground at G503.