Climate Control
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. Refer to the symptom troubleshooting index. Heating/Air Conditioning
- Before doing any symptom troubleshooting, check for powertrain DTCs.
1. Check for body DTCs using B-CAN system diagnosis test mode A troubleshooting.
Are there any DTCs indicated?
YES - Do the appropriate troubleshooting for the DTC indicated.
NO - Go to step 2.
2. Disconnect the A/C pressure switch 4P connector.
3. Turn the ignition switch ON (II).
4. Measure the voltage between the A/C pressure switch 4P connector terminal No. 4 and body ground.
Is there 5 V or more?
YES - Go to step 5.
NO - Go to step 19.
5. Connect the A/C pressure switch 4P connector terminal No. 4 to body ground with the jumper wire.
6. Start the engine
Does the compressor and fans come on?
YES - Go to step 7.
NO - Check the connection of under-hood fuse/relay box connector H terminal No. 9. If the connection is OK, replace the under-hood fuse/relay box.
7. Disconnect the jumper wire, and turn the ignition switch OFF.
8. Check for continuity between the A/C pressure switch terminals No. 1 and No. 4.
Is there continuity?
YES - Go to step 9.
NO - Go to step 18.
9. Reconnect the A/C pressure switch 4P connector.
10. Disconnect climate control unit 30P connector.
11. Turn the ignition switch ON (II).
12. Measure the voltage between the climate control unit 30P connector terminal No. 29 and body ground.
Is there 5 V or more?
YES - Go to step 13.
NO - Repair the open in the wire between the climate control unit and the A/C pressure switch.
13. Turn the ignition switch OFF.
14. Measure the evaporator temperature sensor resistance between the climate control unit 30? connector terminals No. 7 and No. 22.
Is the resistance less than 24 kOhms?
YES - Go to step 15.
NO - Test the evaporator temperature sensor.
15. Reconnect the climate control unit 30P connector.
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 the climate control unit 30? connector and at the A/C pressure switch 4P 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 the problem in the blower motor circuit.
18. 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.
19. Disconnect under-hood relay box connector H (18P).
20. Check for continuity between the A/C pressure switch connector terminal No. 4 and under-hood relay box connector H (18P)-terminal No. 3.
Is there continuity?
YES - Go to step 21.
NO - Repair open in the wire between the relay control module and the A/C pressure switch.
21. Reconnect under-hood relay box connector H (18P).
22. Connect the A/C pressure switch connector terminal No. 4 to body ground with the jumper wire.
23. Start the engine.
Do the A/C compressor and fans come on?
YES - Replace the relay control module.
NO - Check for loose wires or poor connections. If the connections are good, check the grounds. If the grounds are good, replace the relay control module.