| 1. | Disconnect the A/C pressure switch 2P connector. |
| 2. | Turn the ignition switch ON (II). |
| 3. | Measure the voltage between the No. 2 terminal of the A/C pressure switch 2P connector and body ground.
Is there about 5 V? YES - Go to 4. NO - Go to 18. |
| 4. | Turn the ignition switch OFF. |
| 5. | Check for continuity between the No. 1 and No. 2 terminals of the A/C pressure switch.
Is there continuity? YES - Go to 6. NO - Go to 23. |
| 6. | Reconnect the A/C pressure switch 2P connector. |
| 7. | Disconnect climate control unit connector A (12P). |
| 8. | Turn the ignition switch ON (II). |
| 9. | Measure the voltage between the No. 5 terminal of climate control unit connector A (12P) and body ground.
Is there about 5 V? YES - Go to 10. NO - Repair open in the wire between the A/C pressure switch and the climate control unit.n |
| 10. | Turn the ignition switch OFF. |
| 11. | Disconnect the A/C switch 5P connector. |
| 12. | Turn the ignition switch ON (II). |
| 13. | Measure the voltage between the No. 2 terminal of the A/C switch 5P connector and body ground.
Is there battery voltage? YES - Go to 14. NO - Repair open in the wire between the No. 22 fuse in the under-dash relay box and the A/C switch.n |
| 14. | Turn the ignition switch OFF. |
| 15. | Test the A/C switch. Is the A/C switch OK? YES - Go to 16. NO - Repair the A/C switch.n |
| 16. | Check for continuity between the No. 2 terminal of climate control unit connector A (12P) and the No. 1 terminal of the A/C switch 5P connector.
Is there continuity? YES - Go to 17. NO - Repair open in the wire between the climate control unit and the A/C switch.n |
| 17. | Check for continuity between the No. 2 terminal of climate control unit connector A (12P) and body ground.
Is there continuity? YES - Repair short to body ground in the wire between the climate control unit and the A/C switch.n NO - Check for loose wires or poor connections at climate control unit connector A (12P), the A/C pressure switch 2P connector and at the A/C switch 5P 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 |
| 18. | Turn the ignition switch OFF. |
| 19. | Reconnect the A/C pressure switch 2P connector. |
| 20. | Make sure the A/C switch is OFF. |
| 21. | Turn the ignition switch ON (II). |
| 22. | Messure the voltage between the No. 28 terminal of ECM/PCM connector E (31P) and body ground with the ECM/PCM connectors connected.
Is there about 5 V? YES - Repair open in the wire between the ECM/PCM and the A/C pressure switch.n NO - Check for loose wires or poor connections at ECM/PCM connector E (31P) and at the A/C pressure switch 2P connector. If the connections are good, substitute a known-good ECM/PCM, and recheck. If the symptom/indication goes away, replace the original ECM/ PCM.n |
| 23. | Check for proper A/C system pressure. Is the pressure within specifications? YES - Replace the A/C pressure switch.n NO - Repair the A/C pressure problem.n |