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  -Do the A/C pressure switch circuit troubleshooting:

   • With climate control (see A/C PRESSURE SWITCH CIRCUIT TROUBLESHOOTING ).
   • Without climate control (see A/C PRESSURE SWITCH CIRCUIT TROUBLESHOOTING ).
5. Check the A/C system.

   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

Courtesy 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 PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM (see PCM REPLACEMENT ). ■

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