A/C Signal Circuit Troubleshooting
- Do not use this troubleshooting procedure if any of the following items are operative: A/C condenser fan, radiator fan, A/C compressor. Refer to the SYMPTOM TROUBLESHOOTING INDEX .
- Do not use this troubleshooting procedure if the A/C system pressure is abnormal (see A/C PRESSURE SENSOR ).
- Before doing symptom troubleshooting, check for powertrain DTCs (see GENERAL TROUBLESHOOTING INFORMATION ) and B-CAN DTCs (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).
- Turn the ignition switch to LOCK (0).
- Connect the HDS to the DLC.
- Turn the ignition switch to ON (II).
- Check that the blower motor operates at all speeds.
Does the blower motor operate at all speeds?
YES -Go to step 5.
NO -Repair the problem in the blower motor circuit.
- Start the engine.
- Turn on the A/C.
- Check the A/C switch in the PGM-FI Data List with the HDS.
Is the A/C switch on?
YES -The A/C signal is OK at this time.
NO -Go to step 8.
- Check the A/C pressure sensor in the data list.
Is the A/C pressure sensor within specification?
YES -Go to step 9.
NO -Check for poor or loose connections at the A/C pressure sensor. If the connections are OK, replace the A/C pressure sensor.
- Turn the ignition switch to LOCK (0).
- Disconnect the climate control unit 36P connector.
- Turn the ignition switch to ON (II)
- Measure the voltage between climate control unit 36P connector terminal No. 30 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there battery voltage?
YES -Go to step 19.
NO -Go to step 13.
- Turn the ignition switch to LOCK (0).
- Disconnect the A/C compressor clutch 3P connector.
- Turn the ignition switch to ON (II).
- Measure the voltage between A/C compressor clutch 3P connector terminal No. 1 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there battery voltage?
YES -Go to step 17.
NO -Repair an open in the wire between the A/C compressor and the under-dash fuse/relay box. If the wire is OK, substitute a known-good under-dash fuse/relay box, and recheck. If the symptom goes away, replace the original under-dash fuse/relay box.
- Test the A/C compressor thermal protector (see A/C COMPRESSOR CLUTCH CHECK
).
Is the A/C compressor thermal protector OK?
YES -Go to step 18.
NO -Replace the A/C compressor thermal protector (see A/C COMPRESSOR THERMAL PROTECTOR REPLACEMENT ).
- Check for continuity between climate control unit 36P connector terminal No. 30 and A/C compressor clutch 3P connector terminal No. 3.Fig 3: Checking Continuity Between Climate Control Unit 36P Connector Terminal No. 30 And A/C Compressor Clutch 3P Connector Terminal No. 3
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES -Check for loose wires or poor connections at the climate control unit 36P connector and at the A/C compressor clutch 3P connector.
NO -Repair an open in the wire between the climate control unit and A/C compressor.
- Turn the ignition switch to LOCK (0).
- Measure the evaporator temperature sensor resistance between climate control unit 36P connector terminals No. 12 and No. 16.Fig 4: Measuring Evaporator Temperature Sensor Resistance Between Climate Control Unit 36P Connector Terminals No. 12 And No. 16
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is the resistance less than 24 kΩ?
YES -Check for loose wires or poor connections at climate control unit 36P 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 (see CLIMATE CONTROL UNIT REMOVAL/INSTALLATION ).
NO -Test the evaporator temperature sensor (see RECIRCULATION CONTROL MOTOR TEST ).