A/C Pressure Switch Circuit Troubleshooting

NOTE:

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 (see GENERAL TROUBLESHOOTING INFORMATION ).

Disconnect the A/C pressure switch 2P connector.
Turn the ignition switch ON (II).
Measure the voltage between the No. 2 terminal of the A/C pressure switch 2P connector and body ground.

Fig 1: Measuring Voltage Between Terminal Of A/C Pressure Switch 2P Connector And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES - Go to step 4.
2. NO - Go to step 12.
Turn the ignition switch OFF.
Check for continuity between the No. 1 and No. 2 terminals of the A/C pressure switch.

Fig 2: Checking Continuity Between Terminals Of A/C Pressure Switch
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Go to step 6.
2. NO - Go to step 14.
Reconnect the A/C pressure switch 2P connector.
Disconnect the climate control unit 30P connector.
Turn the ignition switch ON (II).
Measure the voltage between the No. 24 terminal of the climate control unit 30P connector and body ground.

Fig 3: Measuring Voltage Between Terminal Of Climate Control Unit 30P Connector And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES - Go to step 10.
2. NO - Repair open in the wire between the climate control unit and the A/C pressure switch.
Turn the ignition switch OFF.
Measure the resistance between the No. 2 and No. 5 terminals of the climate control unit 30P connector.

Fig 4: Measuring Resistance Between Terminals Of Climate Control Unit 30P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the resistance less than 24 kΩ,?
1. 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.
2. NO - Repair cause of high resistance in the evaporator temperature circuit.
Make sure the A/C switch is OFF.
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.

Fig 5: Measuring Voltage Between Terminal Of Under-Dash Fuse/Relay Box Connector F (12P) And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES - Repair open in the wire between the under-dash fuse/relay box and the A/C pressure switch.
2. NO - Refer to the multiplex control system troubleshooting (see TROUBLESHOOTING ).
Check for proper A/C system pressure (see A/C SYSTEM TEST ).
Is the pressure within specifications?
1. YES - Replace the A/C pressure switch.
2. NO - Repair the A/C pressure problem.