Rear Blower Motor Circuit
DTC Troubleshooting: B1223 (1)
DTC B1223 or DTC indicator 1:
A Problem in the Rear Blower Motor Circuit
1. Clear the DTCs with the HDS.
2. Turn the ignition switch to LOCK (0) and then back to ON (II).
3. Do the self-diagnostic function with the HDS or the HVAC control unit.
4. Check for DTCs.
Is DTC B1223 or 1 indicated?
YES -
Go to step 5.
NO -
Intermittent failure, check for loose wires or poor connections in the rear blower motor circuit.�
5. Turn the ignition switch to LOCK (0).
6. Check the No. 5 (RR BLOWER) (30 A) fuse in the auxiliary under-hood fuse/relay box and the No. 36 (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. 5 (RR BLOWER) (30 A) and No. 36 (10 A) fuse(s) circuit.�
7. Connect 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 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 G801.�
13. Connect 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 an 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 HVAC control unit connectors A (24P) and B (16P).
18. Check for continuity between body ground and HVAC control unit connector A (24P) terminal No. 13 and HVAC control unit connector B (16P) terminal No. 11 individually.
Is there continuity?
YES -
Repair a short to body ground in the wire(s) between the HVAC control unit and the rear power transistor.�
NO -
Go to step 19.
19. Check for continuity between the following terminals of HVAC control unit connectors A (24P), B (16P) and the rear power transistor 4P connector.
Is there continuity?
YES -
Go to step 20.
NO -
Repair an open in the wire(s) between the HVAC control unit and the rear power transistor.�
20. Turn the ignition switch to ON (II).
21. Measure the voltage between body ground and HVAC control unit connector A (24P) terminal No. 13 and HVAC control unit connector B (16P) terminal No. 11 individually.
Is there any voltage?
YES -
Repair a short to power in the wire(s).�
NO -
Go to step 22.
22. Reconnect HVAC control unit connectors A (24P) and B (16P).
23. Test the rear power transistor .
Is the rear power transistor OK?
YES -
Check for loose wires or poor connections at HVAC control unit connector A (24P) and at the rear power transistor 4P connector. If the connections are good, substitute a known-good HVAC control unit, and recheck. If the symptom/indication goes away, replace the original HVAC control unit HVAC Control Unit Removal/Installation.�
NO -
Replace the rear power transistor.�
24. Disconnect the jumper wire.
25. Disconnect the rear blower motor 2P connector.
26. 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.�
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 Testing and Inspection.
Is the relay OK?
YES -
Go to step 29.
NO -
Replace the rear blower motor relay.�
29. Measure the voltage between rear blower motor relay 4P socket terminal No. 1 and body ground.
Is there battery voltage?
YES -
Go to step 30.
NO -
Repair an open in the wire between the No. 5 (RR BLOWER) (30 A) in the auxiliary under-hood fuse/relay box and the rear blower motor relay.�
30. Turn the ignition switch to ON (II).
31. Measure the voltage between rear blower motor relay 4P socket terminal No. 2 ('09-10 models) or No. 4 ('11 model) and body ground.
Is there battery voltage?
YES -
Go to step 32.
NO -
Repair an open in the wire between the No. 36 (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 rear blower motor relay 4P socket terminal No. 4 ('09-10 models) or No. 3 ('11 model) and body ground.
Is there continuity?
YES -
Repair an open in the GRY wire between the rear blower motor relay and the rear 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 G801.�