A/C Pressure Switch Circuit Troubleshooting
A/C Pressure Switch Circuit TroubleshootingNote:
- Do not use this troubleshooting procedure if any of the following items are operative; condenser fan, radiator fan, A/C compressor, or if the heater is inoperative, refer to the Symptom Troubleshooting index. Testing and Inspection
- Before performing symptom troubleshooting, check for power train DTCs. Testing and Inspection
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 battery voltage?
YES - Go to step 4.
N0 - 01 Model: Go to step 15.
02-04 Model: Go to step 10
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 step 6.
NO - Go to step 20.
6. Reconnect the A/C pressure switch 2P connector.
7. Disconnect heater control panel connector A (14P).
8. Turn the ignition switch ON (II).
9. Measure the voltage between the No.4 terminal of heater control panel connector A (14P) and body ground.
Is there battery voltage?
YES - Go to step 10.
NO - Repair open in the wire between the heater control panel and the A/C pressure switch.
10. Turn the ignition switch OFF.
11. Disconnect the heater control panel connector B (22P).
12. Measure the resistance between the No.2 terminal of the heater control panel connector A (14P) and the No. 7 terminal of the heater control panel connector B (22P).
Is the resistance lass than 24 K ohms?
YES - Check for loose wires or poor connections at heater control panel connector A (14P) and B (22P) and at the A/C pressure switch 2P connector. If the connections are good, substitute a known-good heater control panel, and recheck. If the symptom/indication goes away, replace the original heater control panel.
NO - Repair cause of high resistance in the evaporator temperature circuit.
13. Turn the ignition switch OFF.
14. Disconnect the compressor clutch 3P connector.
15. Check for continuity between the No. 2 terminal of the A/C pressure switch 2P connector and the No. 3 terminal of the compressor clutch 3P connector.
Is there continuity?
YES - Go to step 16.
NO - Repair open in the wire between the A/C pressure switch and the compressor clutch.
16. Turn the ignition switch ON (II).
17. Measure the voltage between the No.1 terminal of the compressor clutch 3P connector and body ground.
Is there battery voltage?
YES - Check the thermal protector.
NO - Go to step 18.
18. Make sure the A/C switch is OFF.
19. Measure the voltage between the No.9 terminal of under-dash fuse/relay box connector F (12P) and body ground with the under-dash fuse/relay box connectors connected.
Is there battery voltage?
YES - 01 Model: Repair open in the wire between the under-dash fuse/relay box and the A/C pressure switch.
02-04 Model: Repair open in the wire between the under-dash fuse/relay box and the compressor clutch.
NO - Refer to the multiplex control system.
20. Check for proper A/C system pressure.
Is there continuity?
YES - Replace the A/C pressure switch.
NO - Repair the A/C pressure problem.