## A/C Pressure Switch Circuit Troubleshooting - With Climate Control

NOTE:

- Do not use this troubleshooting procedure if any of the following items are operative; condenser fan, radiator fan, A/C compressor. Refer to the symptom troubleshooting index.
- Before performing symptom troubleshooting, check for power train DTCs.

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 5 V or more? 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 28P connector.

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

9. | Measure the voltage between the No. 26 terminal of climate control unit 28P connector and body ground. Is there 5 V or more? YES - With ETCS: Go to 10. Without ETCS: Go to 12. NO - Repair the open in the wire between the climate control unit and the A/C pressure switch.n

10. | Turn the ignition switch OFF.

11. | Check for continuity between the No. 21 terminal and the No. 18 terminal of climate control unit 28P connector. Is there resistance less than 24 k ohms? YES - Go to 15. NO - Repair cause of high resistance in the evaporator temperature circuit.n

12. | Turn the ignition switch OFF.

13. | Disconnect PCM connector E (31P).

14. | Check for continuity between the No. 22 terminal of climate control unit 28P connector and the No. 4 terminal of the PCM connector E (31P). Is there resistance less than 24 k ohms? YES - Go to 15. NO - Repair cause of high resistance in the evaporator temperature circuit.n

15. | Reconnect climate control unit 28P connector and PCM connector E (31P) (without ETCS).

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

17. | Check that blower motor operates at all speeds. Does the blower motor operate at all speeds? YES - Check for loose wires or poor connections at climate control unit 28P connector and at the A/C pressure switch 2P 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 - Repair the problem in the blower motor circuit.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. | Measure the voltage between the No. 40 terminal of ECM connector E (40P) (with ETCS) or the No. 28 terminal of PCM connector E (31P) (without ETCS) and body ground with the ECM/PCM connectors connected. With ETCS Without ETCS Is there 5 V or more? 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 connector E (40P) (with ETCS) or PCM connector E (31P) (without ETCS). 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