Air Conditioning Switch: Testing and Inspection
A/C Pressure Switch Circuit Troubleshooting1. Disconnect the A/C pressure switch 4P connector.
2. Turn the ignition switch ON (II).
3. Measure the voltage between the No. 1 terminal of the A/C pressure switch 4P connector and body ground.
Is there battery voltage?
YES - Go to step 4.
NO - Repair open in the wire between the A/C diode, the ECM and the A/C pressure switch.
4. Turn the ignition switch OFF.
5. Check for continuity between the No. 1 and No. 4 terminals of the A/C pressure switch.
Is there continuity?
YES - Go to step 6.
NO - Go to step 10.
6. Reconnect the A/C pressure switch 4P connector.
7. Disconnect climate control unit connector B (22P).
8. Turn the ignition switch ON (II).
9. Measure the voltage between the No. 17 terminal of climate control unit connector B (22P) and body ground.
Is there battery voltage?
YES - Check for loose wires or poor connections at climate control unit connector B (22P) 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 open in the wire between the climate control unit and the A/C pressure switch.
10. 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.