Climate Control Unit A/C Signal Circuit Troubleshooting

Climate Control Unit A/C Signal Circuit Troubleshooting

NOTE:

- Do not use this troubleshooting procedure if any of the following items are operative: A/C condenser fan, radiator fan, A/C compressor. Refer to the symptom troubleshooting index.

- Do not use this troubleshooting procedure if the A/C system pressure is abnormal. Description and Operation

- Before doing symptom troubleshooting, check for powertrain DTCs. Initial Inspection and Diagnostic Overview

1. Connect the HDS to the DLC.

2. Start the engine.

3. Turn on the A/C.

4. Check the A/C switch in the PGM-FI Data List with the HDS.

Is the A/C switch on?
YES - The A/C signal is OK at this time.

NO - Go to step 5.


5. Turn the ignition switch to LOCK (0).

6. Disconnect the climate control unit connector A (32P).

7. Measure the evaporator temperature sensor resistance between climate control unit connector A (32P) terminals No. 8 and No. 19.

Is the resistance less than 24 kOhms?
YES - Go to step 8.

NO - Test the evaporator temperature sensor. Evaporator Temperature Sensor Test






8. Reconnect climate control unit connector A (32P).

9. Turn the ignition switch to ON (II).

10. Check that the blower motor operates at all speeds.

Does the blower motor operate at all speeds?
YES - Go to step 11.

NO - Repair the problem in the blower motor circuit.


11. Turn the ignition switch to LOCK (0).

12. Disconnect climate control unit connector A (32P).

13. Turn the ignition switch to ON (II).

14. Measure the voltage between climate control unit connector A (32P) terminal No. 6 and body ground.

Is there battery voltage?
YES - Go to step 15.

NO - Repair open in the wire between the climate control unit and MICU.






15. Turn the ignition switch to LOCK (0).

16. Reconnect climate control unit connector A (32P).

17. Set the A/C button and fan control switch ON, then turn the ignition switch to ON (II).

18. Measure the voltage between climate control unit connector A (32P) terminal No. 6 and body ground.

Is there 0.5 V or less?
YES - Replace the MICU. Under-Dash Fuse/Relay Box Removal and Installation

NO - Check for loose wires or poor connections at climate control unit connector A (32P). If the connections are good, substitute a known-good climate control unit and recheck. If the symptom/indication goes away, replace the original climate control unit. Climate Control Unit Removal/Installation