A/C Signal Circuit Troubleshooting

1.Turn the ignition switch ON (II).

2.Momentarily connect ECM/PCM connector terminals A24 and E18 with a jumper wire several times.

 

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


YES - Go to 3.


NO - Go to 6.


3.Start the engine.

4.Turn the blower switch ON.

5.Turn the A/C switch ON.

Does the A/C operate?


YES - The air conditioning signal is OK.n


NO - Substitute a known-good ECM/PCM and recheck. If symptom/indication goes away, replace the original  ECM/ PCM.n

6.Momentarily connect the under-hood fuse/relay box 14P connector terminal No. 10 to body ground with a jumper wire several times.

 

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


YES - Repair open in the wire between the  ECM/ PCM (E18) and the A/C clutch relay.n


NO - Check the A/C system for other symptoms.n