## DTC Troubleshooting: 12

DTC 12: | A Problem in the Blower Motor Circuit

1. | Check the No. 5 (40A) fuse in the under-hood fuse/relay box, and the No. 22 (7.5A) fuse in the under-dash fuse/relay box. Are the fuses OK? YES - Go to 2. NO - Replace the fuse(s), and recheck.n

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

3. | Turn the ignition switch ON (II). Does the blower motor run? YES - Go to 4. NO - Go to 17.

4. | Turn the ignition switch OFF.

5. | Disconnect the jumper wire.

6. | Disconnect the power transistor 4P connector.

7. | Check for continuity between the No. 2 terminal of the power transistor 4P connector and body ground. Is there continuity? YES - Go to 8. NO - Check for an open in the wire between the power transistor and body ground. If the wire is OK, check for poor ground at G402.n

8. | Connect the No. 2 and No. 4 termials of the power transistor 4P connector with a jumper wire.

9. | Turn the ignition switch ON (II). Does the blower motor run at high speed? YES - Go to 10. NO - Repair open in the wire between the power transistor and the blower motor.n

10. | Turn the ignition switch OFF.

11. | Disconnect the jumper wire.

12. | Disconnect climate control unit connector B (16P).

13. | Check for continuity between the No. 15 and No. 16 terminals of climate control unit connector B (16P) and body ground individually. Is there continuity? YES - Repair any short to body ground in the wire(s) between the climate control unit and the power transistor.n NO - Go to 14.

14. | Check for continuity between the following terminals of climate control unit connector B (16P) and power transistor 4P connector.
16P: | 4P:
No. 15 | No. 1
No. 16 | No. 3
Is there continuity? YES - Go to 15. NO - Repair any open in the wire(s) between the climate control unit and the power transistor.n

15. | Reconnect climate control unit connector B (16P).

16. | Test the power transistor. Is the power transistor OK? YES - Check for loose wires or poor connections at climate control unit connector B (16P) and at the 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.n NO - Replace the power transistor.n

17. | Disconnect the jumper wire.

18. | Disconnect the blower motor 2P connector.

19. | Measure the voltage between the No. 1 terminal of the blower motor 2P connector and body ground. Is there battery voltage? YES - Replace the blower motor.n NO - Go to 20.

20. | Turn the ignition switch OFF.

21. | Remove the blower motor relay from the relay holber, and test it. Is there relay OK? YES - Go to 22. NO - Replace the blower motor relay.n

22. | Measure the voltage between the No. 1 terminal of the blower motor relay 5P socket and body ground. Is there battery voltage? YES - Go to 23. NO - Repair open in the wire between the No. 5 fuse in the under-hood fuse/relay box and the blower motor relay.n

23. | Turn the ignition switch ON (II).

24. | Measure the voltage between the No. 5 terminal of the blower motor relay 5P socket and body ground. Is there battery voltage? YES - Go to 25. NO - Repair open in the wire between the No. 22 fuse in the under-dash fuse/relay box and the blower motor relay.n

25. | Turn the ignition switch OFF.

26. | Check for continuity between the No. 3 terminal of the blower motor relay 5P socket and body ground. Is there contnuity? YES - Repair open in the wire between the blower motor relay and the blower motor.n NO - Check for an open in the wire between the blower motor relay and body ground. If the wire is OK, check for poor ground at G402.n