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A/C Signal Circuit Troubleshooting

  1. Start the engine.
  2. Turn the blower switch on.
  3. Turn the A/C switch on.
  4. Check the A/C CLUTCH in the DATA LIST with the HDS.

    Does it indicate ON? 

    YES  -Go to step 5.

    NO  -Check the A/C system (see GENERAL TROUBLESHOOTING INFORMATION ).

  5. Check the A/C system operation.

    Does the A/C system operate? 

    YES  -The air conditioning system circuit is OK.

    NO  -Go to step 6.

  6. Turn the ignition switch to LOCK (0).
  7. Turn the ignition switch to ON (II).
  8. Activate the A/C CLUTCH in the INSPECTION MENU with the HDS.

    Is there a clicking noise from the A/C compressor clutch? 

    YES  -Do the A/C system test (see A/C SYSTEM TEST ).

    NO  -Go to step 9.

  9. Turn the ignition switch to LOCK (0).
  10. Jump the SCS line with the HDS.
  11. Disconnect PCM connector A (49P).
  12. Turn the ignition switch to ON (II).
  13. Momentarily connect PCM connector terminal A13 to body ground with a jumper wire several times.
    Fig 1: Connecting PCM Connector Terminal A13 To Body Ground With Jumper Wire
    G08052500Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there a clicking noise from the A/C compressor clutch? 

    YES  -Update the PCM if it does not have the latest software (see KNOCK SENSOR REPLACEMENT ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the symptom/indication goes away and the PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the PCM was substituted, replace the original PCM (see PCM REPLACEMENT ).

    NO  -Check for poor connections or loose terminals at the A/C compressor clutch relay and the PCM. If the connections are OK, check the A/C compressor clutch relay (see POWER RELAY TEST ). If needed, repair an open in the wire between the PCM (A13) and the A/C compressor clutch relay and the other A/C system parts.