HVAC System Test

Possible Causes:

Attempt to communicate with the PCM or the CTM.
Check for HVAC DTCs in the PCM.
Check for CTM DTCs.
Check for active HVAC DTCs.
Manual A/C System Test.

CAUTION: Always turn ignition off before disconnecting or connecting any control module connector. Failure to do so could result in damage to control module.

NOTE: Ensure vehicle being tested has a fully charged battery. If it does not, false symptoms may occur.

NOTE: For component location, see appropriate illustration under COMPONENT LOCATIONS . For terminal identification, see appropriate illustration under CONNECTOR IDENTIFICATION . For circuit and wire color identification, see WIRING DIAGRAMS . For component removal and installation procedures, see appropriate component under REMOVAL & INSTALLATION .

Testing:

Turn ignition off. Connect DRBIII(R) to DLC. Turn ignition on. Using the DRBIII(R), attempt to communicate with the PCM and the CTM. Is DRBIII(R) able to identify or communicate with the PCM and the CTM? If yes, go to next step. If no, see PCI BUS COMMUNICATION FAILURE under COMMUNICATION SYSTEM.
Using the DRBIII(R), read PCM DTCs. Are any HVAC-related DTCS present? If yes, see SELF-DIAGNOSTICS - DURANGO - JTEC or SELF-DIAGNOSTICS - DURANGO - NGC article in ENGINE PERFORMANCE. If no, go to next step.
Using the DRBIII(R), read CTM DTCs. Are any DTCS present? If yes, perform appropriate DTC test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.

NOTE: The Evaporator temperature must be more than 65°F (18.3°C) and the work area ambient temperature must be more than 70°F (21.1°C) to test HVAC system operation. Active DTCs must be diagnosed before diagnosing stored DTCs. Anytime a DTC becomes active, or a Cool Down Test DTC, Actuator Circuit Test DTC of Door Recalibration DTC is displayed, proceed directly to the conclusion question answers (If yes/If no).

Start the Engine. Turn the Front/Rear Mode Select Control to the panel position. Verify that the Front Blower Motor and Rear Blower Motor (if equipped) operates correctly in all speeds from each control. Is the Blower Motor operating properly? If yes, go to next step. If no, Diagnose and repair all Blower Motor-related faults before proceeding with this test. Perform BODY VERIFICATION TEST under VERIFICATION TESTS.
Turn ignition off. Connect DRBIII(R) to DLC. Start the engine. Turn the Blower Motor Control to the high speed position. Using the DRBIII(R) select HVAC, SYSTEM TESTS, then actuate the A/C Cool Down Test. Turn the Blower Motor Control to the low speed position. Turn the Rear Blower Motor Control (if equipped) to the Rear Control position. Turn the Passenger/Rear Blend Control to the full cold position. Turn the Driver Blend Control to the full cold position. Turn the Rear Blend Control (if equipped) on the Rear A/C-Heater Control Module to the full cold position. Monitor the DRBIII(R) for active HVAC DTCs while performing the following before proceeding to next step:
- Press A/C On/Off switch on, wait 30 seconds, then press it off.
- Press EBL switch on, wait 30 seconds, then press it off.
- Press and hold the Rear Wiper/Wash Switch for 5 seconds, then release it.
- Turn the Driver Blend Control from full cold to full hot, wait 30 seconds, then turn it back to full cold.
- Turn the Passenger/Rear Blend Control from full cold to full hot, wait 30 seconds, then turn it back to full cold.
- Turn the Front/Rear Mode Select Control to every door position. Leave it in each position for approximately 30 seconds.
- Turn the Rear Blend Control (if equipped) on the Rear A/C-Heater Control Module from full cold to full hot, wait 30 seconds, then turn it back to full cold.
Using the DRBIII(R), actuate the Actuator Circuit Test, then actuate the HVAC Door Recalibration. Does the DRBIII(R) display any HVAC DTCs? If yes, perform appropriate DTC test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
Using the DRBIII(R), read PCM DTCs. Are any HVAC-related PCM DTCs present? If yes, see SELF-DIAGNOSTICS - DURANGO - JTEC or SELF-DIAGNOSTICS - DURANGO - NGC article in ENGINE PERFORMANCE. If no, return to step 1 .