Blower Motor Circuit Troubleshooting
Blower Motor Circuit Troubleshooting
1. Turn the ignition switch to ON (II) and the heater fan switch ON.
Does the blower motor run at each speed?
YES -
Go to step 2.
NO -
Go to step 4.
2. Turn the heater fan switch OFF.
3. Make sure the ignition switch is ON (II).
Does the blower motor run?
YES -
Go to step 27.
NO -
Intermittent problem. Check for loose wire or poor connections on the blower motor circuit.�
4. Measure the voltage between blower motor 2P connector terminal No. 1 and body ground.
Is there battery voltage?
YES -
Go to step 5.
NO -
Go to step 9.
5. Turn the ignition switch to LOCK (0).
6. Ground blower motor connector terminal No. 2 with a jumper wire.
7. Turn the ignition switch to ON (II).
Does the blower motor run?
YES -
Go to step 17.
NO -
Replace the blower motor Blower Unit Component Replacement.�
8. Turn the ignition switch to LOCK (0).
9. Check the No. 57 (30 A) and the No. 10 (7.5 A) fuses in the under-dash fuse/relay box.
Are the fuses OK?
YES -
Go to step 10.
NO -
Replace the blown fuses, and recheck. If either fuse blows again, check for a short in the No. 57 (30 A) or the No. 10 (7.5 A) fuse circuits.�
10. Measure the voltage between blower motor relay 4P socket terminal No. 1 and body ground.
Is there battery voltage?
YES -
Go to step 11.
NO -
Replace the under-dash fuse/relay box Under-dash Fuse/Relay Box Removal And Installation (USA Models).�
11. Turn the ignition switch to ON (II).
12. Measure the voltage between blower motor relay 4P socket terminal No. 3 and body ground.
Is there battery voltage?
YES -
Go to step 13.
NO -
Replace the under-dash fuse/relay box Under-dash Fuse/Relay Box Removal And Installation (USA Models).�
13. Turn the ignition switch to LOCK (0).
14. Check for continuity between blower motor relay 4P socket terminal No. 4 and body ground.
Is there continuity?
YES -
Go to step 15.
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 G501 [1][2]Harness.�
15. Turn the ignition switch to ON (II).
16. Measure the voltage between blower motor relay 4P socket terminal No. 2 and body ground.
Is there battery voltage?
YES -
Repair an open in the wire between the blower motor relay and the blower motor.�
NO -
Replace the blower motor relay.�
17. Turn the ignition switch to LOCK (0).
18. Disconnect the jumper wire.
19. Disconnect the blower resistor 4P connector.
20. Test the blower resistor Blower Resistor Test.
Is the blower resistor OK?
YES -
Go to step 21.
NO -
Replace the blower resistor.�
21. Reconnect the blower resistor 4P connector.
22. Disconnect the heater fan switch 8P connector.
23. Turn the ignition switch to ON (II).
24. Ground each of the heater fan switch 8P connector terminals with a jumper wire individually in the following order: No. 4, 7, 8, and 2.
Does the blower motor run at progressively higher speeds?
YES -
Go to step 25.
NO -
Repair an open in the wires between the blower resistor and the heater fan switch.�
25. Turn the ignition switch to LOCK (0).
26. Check for continuity between heater fan switch 8P connector terminal No. 1 and body ground.
Is there continuity?
YES -
Replace the heater fan switch Overhaul.�
NO -
Check for an open in the wire between the heater fan switch and body ground. If the wire is OK, check for poor ground at G502: With navigation [1][2]Harness, Without navigation [1][2]Harness.�
27. Turn the ignition switch to LOCK (0).
28. Disconnect the blower motor 2P connector.
29. Disconnect the blower resistor 4P connector.
30. Disconnect the heater fan switch 8P connector.
31. Check for continuity between body ground and heater fan switch 8P connector terminals No. 2, 4, 7, and 8 individually.
Is there continuity?
YES -
Repair a short to body ground in the wires between the blower motor, the blower resistor, and the heater fan switch.�
NO -
Replace the heater fan switch Overhaul.�