2004 Acura TL AutomaticFACTORY OEM SERVICE PROCEDURE

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? 

    1. YES  -Go to step 5.
    2. NO  -Do the A/C pressure switch circuit troubleshooting (see A/C PRESSURE SWITCH CIRCUIT TROUBLESHOOTING ).
  5. Check the A/C system.

    Does the A/C system operate? 

    1. YES  -The air conditioning system circuit is OK.
    2. NO  -Go to step 6.
  6. Turn the ignition switch OFF.
  7. Turn the ignition switch 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? 

    1. YES  -Do the A/C system test (see A/C SYSTEM TEST ).
    2. NO  -Go to step 9.
  9. Momentarily connect under-hood fuse/relay box 16P connector terminal No. 15 to body ground with a jumper wire several times.
    Fig 1: Connecting Under-Hood Fuse/Relay Box 16P Connector Terminal 15 To Body Ground With Jumper Wire
    G03659672Courtesy of AMERICAN HONDA MOTOR CO., INC.

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

    1. YES  -Repair open in the wire between the ECM/PCM (A27) (2004-2005 models), (E27) (2006 model) and the A/C clutch relay.
    2. NO  -Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/ PCM (see HOW TO TROUBLESHOOT CIRCUITS AT THE ECM/PCM ), then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ).
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.