Refrigerant Pressure Sensor / Switch: Testing and Inspection
A/C Pressure Switch Circuit TroubleshootingNOTE:
- Do not use this troubleshooting procedure if the following items are operative: A/C condenser fan, radiator fan, A/C compressor, or if the heater is inoperative. Refer to the symptom troubleshooting index.
- Before performing symptom troubleshooting, check for powertrain 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 battery voltage?
YES - Go to step 4.
NO - Go to step 12.
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 14.
6. Reconnect the A/C pressure switch 2P connector.
7. Disconnect the climate control unit 30P connector.
8. Turn the ignition switch ON (II).
9. Measure the voltage between the No. 24 terminal of the climate control unit 30P connector and body ground.
Is there battery voltage?
YES - Go to step 10.
NO - Repair open in the wire between the climate control unit and the A/C pressure switch.
10. Turn the ignition switch OFF.
11. Measure the resistance between the No. 2 and No. 5 terminals of the climate control unit 30P connector.
Is the resistance less than 24 kOhm?
YES - Check for loose wires or poor connections at the climate control unit 30P 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.
NO - Repair cause of high resistance in the evaporator temperature circuit.
12. Make sure the A/C switch is OFF.
13. 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 - Repair open in the wire between the under-dash fuse/relay box and the A/C pressure switch.
NO - Refer to the multiplex control system troubleshooting.
14. Check for proper A/C system pressure.
Is the pressure within specifications?
YES - Replace the A/C pressure switch.
NO - Repair the A/C pressure problem.