Symptom Chart - Climate Control Systems

WARNING: This page is about a different car, the 2015 Lincoln MKT. However, it is still accessible from the selected car via links, so may be relevant.

Condition	Possible Sources	Action
NOTE: Some PCM DTCs may inhibit A/C operation. If any PCM DTCs are retrieved, diagnose those first. Refer to the Engine Controls - Introduction (Except Diesel & Hybrid) .
No communication with the HVAC module	Fuse Wiring, terminals or connectors Communication network HVAC module	REFER to Module Communications Network .
No communication with the RHVAC module	Fuse Wiring, terminals or connectors Communication network RHVAC module	REFER to Module Communications Network .
Externally Controlled Variable Displacement Compressor (EVDC) poor performance/does not operate correctly	Refer to the Diagnostic Routine	GO to Pinpoint Test Y .
Unable to duplicate the customer concern and no DTCs present	Refer to the Diagnostic Routine	GO to Pinpoint Test H .
The HVAC functions are inoperative/do not operate correctly from touchscreen only	Communication network FCDIM	For 8 Inch (203mm) Touchscreen, 10 Speakers, REFER to Information and Entertainment Systems - 8-Inch (203 mm) Touchscreen, 8 Speakers Symptom Chart and DIAGNOSE the touchscreen. For THX, 8 Inch (203mm) Touchscreen, 14 Speakers, REFER to Information and Entertainment Systems - THX® 8-Inch (203 mm) Touchscreen, 14 Speakers Symptom Chart and DIAGNOSE the touchscreen.
HVAC functions are inoperative/do not operate correctly from steering wheel switches/infotainment display only	Steering wheel switches Clockspring SCCM IPC	For 8 Inch (203mm) Touchscreen, 10 Speakers, REFER to Information and Entertainment Systems - 8-Inch (203 mm) Touchscreen, 8 Speakers Symptom Chart and DIAGNOSE the steering wheel switches. For THX, 8 Inch (203mm) Touchscreen, 14 Speakers, REFER to Information and Entertainment Systems - THX® 8-Inch (203 mm) Touchscreen, 14 Speakers Symptom Chart and DIAGNOSE the steering wheel switches.
The air inlet door is inoperative	Refer to the Diagnostic Routine	GO to Pinpoint Test I .
Incorrect/erratic direction of airflow from outlets	Refer to the Diagnostic Routine	GO to Pinpoint Test J .
Reduced outlet airflow	Refer to the Diagnostic Routine	If the A/C compressor does not cycle, GO to Pinpoint Test M . If the A/C compressor cycles normally, GO to Pinpoint Test R .
Insufficient, erratic or no heat	Refer to the Diagnostic Routine	GO to Pinpoint Test K .
The air conditioning (A/C) is inoperative	Refer to the Diagnostic Routine	GO to Pinpoint Test L .
The air conditioning (A/C) is always on - A/C compressor does not cycle	Refer to the Diagnostic Routine	GO to Pinpoint Test M .
The air conditioning (A/C) is always on - A/C mode always commanded ON	Refer to the Diagnostic Routine	GO to Pinpoint Test N .
Temperature control is inoperative/does not operate correctly	Refer to the Diagnostic Routine	GO to Pinpoint Test O .
The blower motor is inoperative	Refer to the Diagnostic Routine	GO to Pinpoint Test Q .
The blower motor does not operate correctly	Refer to the Diagnostic Routine	GO to Pinpoint Test R .
The auxiliary blower motor is inoperative	Refer to the Diagnostic Routine	GO to Pinpoint Test S .
The auxiliary blower motor does not operate correctly	Refer to the Diagnostic Routine	If the auxiliary blower motor does not operate correctly from both the front and rear auxiliary controls, GO to Pinpoint Test T . If the auxiliary blower motor does not operate correctly from the rear auxiliary controls only, CHECK for RHVAC module DTCs. If RHVAC DTCs are present, GO to the Rear Heating Ventilation Air Conditioning (RHVAC) Module DTC Chart . If no RHVAC DTCs are present, INSTALL a new RHVAC module. REFER to Auxiliary Climate Control . TEST the system for normal operation. If the auxiliary blower motor does not operate correctly from the front auxiliary controls only, CHECK for HVAC module DTCs. If HVAC DTCs are present, GO to the HVAC Module DTC Chart . If no HVAC DTCs are present, INSTALL a new HVAC module. REFER to Climate Control . TEST the system for normal operation.
The auxiliary temperature control is inoperative/does not operate correctly using the front/rear auxiliary climate controls	Refer to the Diagnostic Routine	If the auxiliary temperature control is inoperative/does not operate correctly from both the front and rear auxiliary controls, GO to Pinpoint Test U . If the auxiliary temperature control is inoperative/does not operate correctly from the rear auxiliary controls only, CHECK for RHVAC module DTCs. If RHVAC DTCs are present, GO to the Rear Heating Ventilation Air Conditioning (RHVAC) Module DTC Chart . If no RHVAC DTCs are present, INSTALL a new RHVAC module. REFER to Auxiliary Climate Control . TEST the system for normal operation. If the auxiliary temperature control is inoperative/does not operate correctly from the front auxiliary controls only, CHECK for HVAC module DTCs. If HVAC DTCs are present, GO to the HVAC Module DTC Chart . If no HVAC DTCs are present, INSTALL a new HVAC module. REFER to Climate Control . TEST the system for normal operation.
The auxiliary panel/floor control is inoperative/does not operate correctly using the front/rear auxiliary climate controls	Refer to the Diagnostic Routine	If the auxiliary panel/floor control is inoperative/does not operate correctly from both the front and rear auxiliary controls, GO to Pinpoint Test V . If the auxiliary panel/floor control is inoperative/does not operate correctly from the rear auxiliary controls only, CHECK for RHVAC module DTCs. If RHVAC module DTCs are present, GO to the Rear Heating Ventilation Air Conditioning (RHVAC) Module DTC Chart . If no RHVAC DTCs are present, INSTALL a new RHVAC module. REFER to Auxiliary Climate Control . TEST the system for normal operation. If the auxiliary panel/floor control is inoperative/does not operate correctly from the front auxiliary controls only, CHECK for HVAC module DTCs. If HVAC DTCs are present, GO to the HVAC Module DTC Chart . If no HVAC DTCs are present, INSTALL a new HVAC module. REFER to Climate Control . TEST the system for normal operation.
The auxiliary temperature, panel/floor mode or blower motor controls are inoperative/do not operate correctly using the rear auxiliary climate controls only	RHVAC module	CHECK for RHVAC module DTCs. If RHVAC module DTCs are present, GO to the Rear Heating Ventilation Air Conditioning (RHVAC) Module DTC Chart . If no RHVAC DTCs are present, INSTALL a new RHVAC module. REFER to Auxiliary Climate Control . TEST the system for normal operation.
A/C pressure relief valve discharging	High system pressure A/C pressure relief valve	CHECK the high side system pressure. If the pressure is below the A/C pressure relief valve open pressure, INSTALL a new A/C compressor. REFER to Climate Control . If the system pressure is above the A/C pressure relief valve open pressure, REPAIR the system for a restriction.