Skip to main content
A/C Signal Circuit Troubleshooting

  1. Start the engine, and let it idle.
  1. Turn the blower switch on.
  1. Turn the A/C switch on.
  1. Check the A/C CLUTCH in the DATA LIST with the HDS.
Does it indicate ON?
YES -
Go to Step 5 .
NO -
  1. Check the A/C system.
Does the A/C system operate?
YES -
The air conditioning system circuit is OK.■
NO -
Go to Step 6 .
  1. Turn the ignition switch to LOCK (0).
  1. Turn the ignition switch to ON (II).
  1. Activate the A/C CLUTCH in the INSPECTION MENU with the HDS.
Is there a clicking noise from the A/C compressor clutch?
YES -
NO -
Go to Step 9 .
  1. Turn the ignition switch to LOCK (0).
  1. Jump the SCS line with the HDS.
  1. Disconnect ECM/PCM connector A (49P).
  1. Turn the ignition switch to ON (II).
  1. Momentarily connect ECM/PCM connector terminal A15 to body ground with a jumper wire several times.
Is there a clicking noise from the A/C compressor clutch?
YES -
NO -
Check for poor connections or loose terminals at the A/C compressor clutch relay and the ECM/PCM. If the connections are OK, check the A/C compressor clutch relay, repair open in the wire between the ECM/PCM (A15) and the A/C compressor clutch relay and the other A/C systems.■