A/C Signal Circuit Troubleshooting

Start the engine.
Turn the blower switch ON.
Turn the A/C switch ON.
Check the A/C CLUTCH in the DATA LIST with the HDS.
Does it indicate ON?
1. YES - Go to step 5.
2. NO - Go to the A/C pressure switch test (see A/C PRESSURE SWITCH CIRCUIT TROUBLESHOOTING .
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.
Turn the ignition switch OFF.
Turn the ignition switch ON (II).
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.
Turn the ignition switch OFF.
Jump the SCS line with the HDS.
Disconnect PCM connector B (56P).
Turn the ignition switch ON (II).
Momentarily connect PCM connector terminal B11 to body ground with a jumper wire several times.

Fig 1: Connecting PCM Connector Terminal B11 To Body Ground With Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there a clicking noise from the A/C compressor clutch?
1. YES - Update the PCM if it does not have the latest software, or substitute a known-good PCM (see PCM UPDATING AND SUBSTITUTION FOR TESTING ), then recheck. If the symptom/ indication goes away with a known-good PCM, replace the original PCM (see PCM REPLACEMENT ). The air conditioning signal OK.
2. NO - Check for poor connections or loose terminals at the A/C clutch relay and the PCM. If they are OK, check for the A/C clutch relay (see POWER RELAY TEST ), and other A/C systems.