Blower Motor Circuit Troubleshooting
Blower Motor Circuit Troubleshooting
| 1. | Turn the ignition switch ON (II) and the heater fan switch ON. Does the blower motor run? YES - Go to 2. NO - Go to 16. |
| 2. | Turn the heater fan switch OFF. |
| 3. | Make sure the ignition switch is ON (II). Does the blower motor run? YES - Go to 4. NO - Go to 9. |
| 4. | Turn the ignition switch OFF. |
| 5. | Disconnect the blower motor 2P connector. |
| 6. | Disconnect the blower resistor 4P connector. |
| 7. | Disconnect the heater fan switch 7P connector. |
| 8. | Check for continuity between the No. 1, 2, 4 and 5 terminals of the heater fan switch 7P connector and body ground individually.
 HEATER FAN SWITCH 7P CONNECTORWire side of female terminalsRED/YELBLU/BLKRED/BLUYEL/GRNIs there continuity? YES - Repair any short to body ground in the wire(s) between the blower motor, the blower resistor and the heater fan switch.n NO - Replace the heater fan switch.n |
| 9. | Turn the ignition switch OFF. |
| 10. | Disconnect the blower resistor 4P connector. |
| 11. | Measure the resistance between the No. 2 and No. 3 terminals of the blower resistor.
 BLOWER RESISTORIs there about 3-4 W? YES - Go to 12. NO - Replace the blower resistor.n |
| 12. | Reconnect the blower resistor 4P connector. |
| 13. | Disconnect the heater fan switch 7P connector. |
| 14. | Turn the ignition switch ON (II). |
| 15. | Ground each of the heater fan switch 7P connector terminals individually in the following order: No. 1, 2, 4 and 5.
 HEATER FAN SWITCH 7P CONNECTORWire side of female terminalsRED/YELBLU/BLKRED/BLUYEL/GRNDoes the blower motor run at progressively higher speeds? YES - Replace the heater fan switch.n NO - Repair any open or cause of excessive resistance in the appropriate wire(s) between the blower resistor and the heater fan switch.n |
| 16. | Turn the heater fan switch OFF and the ignition switch OFF. |
| 17. | 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 18. NO - Replace the fuse(s), and recheck.n |
| 18. | Connect the No. 2 terminal of the blower motor 2P connector to body ground with a jumper wire.
 BLOWER MOTOR 2P CONNECTORWire side of female terminalsJUMPERWIREBLU/BLK |
| 19. | Turn the ignition switch ON (II). Does the blower motor run? YES - Go to 20. NO - Go to 27. |
| 20. | Turn the ignition switch OFF. |
| 21. | Disconnect the jumper wire. |
| 22. | Disconnect the heater fan switch 7P connector. |
| 23. | Turn the ignition switch ON (II). |
| 24. | Measure the voltage between the No. 5 terminal of the heater fan switch 7P connector and body ground.
 HEATER FAN SWITCH 7P CONNECTORWire side of female terminalsBLU/BLKIs there battery voltage? YES - Go to 25. NO - Repair open in the wire between the blower motor and the heater fan switch.n |
| 25. | Turn the ignition switch OFF. |
| 26. | Check for continuity between the No. 3 terminal of the heater fan switch 7P connector and body ground.
 HEATER FAN SWITCH 7P CONNECTORWire side of female terminalsBLKIs there continuity? YES - Replace the heater fan switch.n 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 G402.n |
| 27. | Disconnect the jumper wire. |
| 28. | Disconnect the blower motor 2P connector. |
| 29. | Measure the voltage between the No. 1 terminal of the blower motor 2P connector and body ground.
 BLOWER MOTOR 2P CONNECTORWire side of female terminalsBLU/WHTIs there battery voltage? YES - Replace the blower motor.n NO - Go to 30. |
| 30. | Turn the ignition switch OFF. |
| 31. | Remove the blower motor relay from the under-dash fuse/relay box, and test it. Is the relay OK? YES - Go to 32. NO - Replace the blower motor relay.n |
| 32. | Measure the voltage between the No. 1 terminal of the blower motor relay 5P socket and body ground.
 BLOWER MOTOR RELAY 5P SOCKETWHT/BLUIs there battery voltage? YES - Go to 33. NO - Repair open in the wire between the No. 5 fuse in the under-hood fuse/relay box and the blower motor relay.n |
| 33. | Turn the ignition switch ON (II). |
| 34. | Measure the voltage between the No. 5 terminal of the blower motor relay 5P socket and body ground.
 BLOWER MOTOR RELAY 5P SOCKETBLK/YELIs there battery voltage? YES - Go to 35. NO - Repair open in the wire between the No. 22 fuse in the under-dash fuse/relay box and the blower motor relay.n |
| 35. | Turn the ignition switch OFF. |
| 36. | Check for continuity between the No. 3 terminal of the blower motor relay 5P socket and body ground.
 BLOWER MOTOR RELAY 5P SOCKETBLKIs there continuity? YES - Repair open in the BLU/WHT 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 |