L
DTC Troubleshooting: B1223 (L)
DTC B1223 or DTC indicator L:
A Problem in the Rear Blower Motor Circuit
1. Clear the DTC by turning the ignition switch to LOCK (0), and then turn to ON (II).
2. Operate the climate control system in several modes.
3. Check for DTCs using the HDS How to Troubleshoot the Climate Control System or self-diagnostic function How to Troubleshoot the Climate Control System.
Is DTC B1223 or L indicated?
YES -
Go to step 4.
NO -
Intermittent failure, check for loose wires or poor connections on the rear blower motor circuit.�
4. Turn the ignition switch to LOCK (0).
5. Check the No. 22 (70 A) fuse in the under-hood fuse/relay box, and the No. 1 (30 A) fuse in the passenger's under-dash fuse/relay box.
Are the fuses OK?
YES -
Go to step 6.
NO -
Replace the fuse(s), and recheck.�
6. Connect rear blower motor 2P connector terminal No. 2 to body ground with a jumper wire.
7. Turn the ignition switch to ON (II).
Does the rear blower motor run?
YES -
Go to step 8.
NO -
Go to step 24.
8. Turn the ignition switch to LOCK (0).
9. Disconnect the jumper wire.
10. Disconnect the power transistor 4P connector.
11. Check for continuity between rear power transistor 4P connector terminal No. 2 and body ground.
Is there continuity?
YES -
Go to step 12.
NO -
Check for an open in the BLK wire between the rear power transistor and body ground. If the wire is OK, check for poor ground at G652.�
12. Connect rear power transistor 4P connector terminals No. 2 and No. 4 with a jumper wire.
13. Turn the ignition switch to ON (II).
Does the rear blower motor run at high speed?
YES -
Go to step 14.
NO -
Repair an open in the BLU/BLK wire between the rear power transistor and the rear blower motor.�
14. Turn the ignition switch to LOCK (0).
15. Disconnect the jumper wire.
16. Disconnect the rear climate control unit 22P connector.
17. Check for continuity between body ground and rear climate control unit 22P connector terminals No. 18 and No. 19 and individually.
Is there continuity?
YES -
Repair a short to body ground in the wire(s) between the rear climate control unit and the power transistor.�
NO -
Go to step 18.
18. Check for continuity between the following terminals of the rear climate control unit 22P connector and rear power transistor 4P connector.
Is there continuity?
YES -
Go to step 19.
NO -
Repair an open in the wire(s) between the rear climate control unit and the rear power transistor.�
19. Start the engine.
20. Measure the voltage between body ground and rear climate control unit 22P connector terminals No. 18 and No. 19 individually.
Is there voltage?
YES -
Repair a short to power in the wires.�
NO -
Go to step 21.
21. Turn the ignition switch to LOCK (0).
22. Reconnect the rear climate control unit 22P connector.
23. Test the rear power transistor Rear Blower Power Transistor Test.
Is the power transistor OK?
YES -
Check for loose wire or poor connections at the rear climate control unit 22P connector and at the rear power transistor 4P connector. If the connections are good, substitute a known-good rear climate control unit, and recheck. If the symptom/indication goes away, replace the original rear climate control unit Rear Climate Control Unit Removal/Installation.�
NO -
Replace the rear power transistor.�
24. Turn the ignition switch to LOCK (0).
25. Disconnect the jumper wire.
26. Disconnect the rear blower motor 2P connector.
27. Turn the ignition switch to LOCK (II).
28. Measure the voltage between 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 29.
29. Turn the ignition switch to LOCK (0).
30. Remove the rear blower motor relay from the rear junction box, and test it Power Relay Test.
Is the relay OK?
YES -
Go to step 31.
NO -
Replace the rear blower motor relay.�
31. Measure the voltage between body ground and rear blower motor relay 4P socket terminals No. 1 and No. 4 individually.
Is there battery voltage?
YES -
Go to step 32.
NO -
Repair an open in the BLK/WHT wire between the passenger's under-fuse/relay box and the rear junction box control unit.�
32. Turn the ignition switch to ON (II).
33. Check for continuity between rear blower motor relay 4P socket terminal No. 3 and body ground.
Is there continuity?
YES -
Substitute a known-good rear junction box, and recheck. If the symptom/indication goes away, replace the original rear junction box.�
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 G652.�