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Home >> Honda >> 2004 >> Pilot EX >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Heating/Air Conditioning >> Compressor Clutch Circuit Troubleshooting
July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Compressor Clutch Circuit Troubleshooting

NOTE:
  • Do not use this troubleshooting procedure if the fans are also inoperative with the A/C on. Refer to the symptom troubleshooting index.
  • Before performing symptom troubleshooting, check for powertrain DTC (see HOW TO USE THE HONDA DIAGNOSTIC SYSTEM (HDS) ).
  1. Check the No. 59 (7.5A) fuse in the under-hood fuse/relay box, and the No. 3 (7.5A) fuse in the driver's under-dash fuse/relay box.

    Are the fuses OK? 

    1. YES  - Go to step 2.
    2. NO  - Replace the fuse(s), and recheck.
  2. Check the engine coolant temperature, throttle position, and idle speed (use the HDS PGM-FI data list if possible).
    Fig 1: Checking HDS PGM-FI Data List
    G01465679Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Are the coolant temperature, throttle position, and idle speed OK? 

    1. YES  - Go to step 3.
    2. NO  - Troubleshoot and repair the cause of the high engine coolant temperature, low idle, or excessively high throttle position sensor reading.
  3. Remove the compressor clutch relay from the under-hood fuse/relay box, and test it (see FUSES & CIRCUIT BREAKERS ).

    Is the relay OK? 

    1. YES  - Go to step 4.
    2. NO  - Replace the compressor clutch relay.
  4. Measure the voltage between the No. 1 terminal of the compressor clutch relay 4P socket and body ground.
    Fig 2: Measuring The Voltage Between The No. 1 Terminal Of The Compressor Clutch Relay 4P Socket & Body Ground
    G01465680Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES  - Go to step 5.
    2. NO  - Replace the under-hood fuse/relay box.
  5. Connect the No. 1 and No. 2 terminals of the compressor clutch relay 4P socket with a jumper wire.
    Fig 3: Connecting The No. 1 & No. 2 Terminals Of The Compressor Clutch Relay 4P Socket With A Jumper Wire
    G01465681Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Does the compressor clutch click? 

    1. YES  - Go to step 6.
    2. NO  - Go to step  15.
  6. Disconnect the jumper wire.
  7. Turn the ignition switch ON (II).
  8. Measure the voltage between the No. 4 terminal of the compressor clutch relay 4P socket and body ground.
    Fig 4: Measuring The Voltage Between The No. 4 Terminal Of The Compressor Clutch Relay 4P Socket & Body Ground
    G01465682Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES  - Go to step 9.
    2. NO  - Repair open in the wire between the No .3 fuse in the driver's under-dash fuse/relay box and the compressor clutch relay.
  9. Turn the ignition switch OFF.
  10. Reinstall the compressor clutch relay.
  11. Make sure the A/C switch is OFF.
  12. Turn the ignition switch ON (II).
  13. Using the backprobe set, measure the voltage between the No. 17 terminal of PCM connector A (32P) and body ground with the PCM connectors connected.
    Fig 5: Measuring The Voltage Between The No. 17 Terminal Of PCM Connector A (32P) & Body Ground
    G01465683Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES  - Go to step 14.
    2. NO  - Repair open in the wire between the compressor clutch relay and the PCM.
  14. Using the backprobe set, measure the voltage between the No. 27 terminal of PCM connector A (32P) and body ground with the PCM connectors connected.
    Fig 6: Measuring The Voltage Between The No. 27 Terminal Of PCM Connector A (32P) & Body Ground
    G01465684Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES  - Check for loose wires or poor connections at PCM connector A (32P). If the connections are good, substitute a known-good PCM, and recheck. If the symptom/indication goes away, replace the original PCM.
    2. NO  - Repair open in the wire between the PCM and the A/C pressure switch.
  15. Disconnect the jumper wire.
  16. Disconnect the compressor clutch 1P connector.
  17. Check for continuity between the No. 2 terminal of the compressor clutch relay 4P socket and the No. 1 terminal of the compressor clutch 1P connector.
    Fig 7: Checking For Continuity Between The No. 2 Terminal Of The Compressor Clutch Relay 4P Socket & The No. 1 Terminal Of The Compressor Clutch 1P Connector
    G01465685Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES  - Check the compressor clutch clearance and the compressor clutch field coil (see COMPRESSOR CLUTCH CHECK  ). Repair as needed.
    2. NO  - Repair open in the wire between the compressor clutch relay and the compressor clutch.
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