Symptom Chart - Climate Control Systems

WARNING: This page is about a different car, the 2016 Lincoln MKS. 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 ENGINE CONTROLS - POWERTRAIN DTC CHARTS & DESCRIPTIONS (EXCEPT DIESEL & HYBRID) .
No communication with the HVAC control module	Fuse Wiring, terminals or connectors Communication network HVAC control module	REFER to COMMUNICATIONS NETWORK .
Externally Controlled Variable Displacement Compressor (EVDC) poor performance/does not operate correctly	Refer to the Pinpoint Test	PINPOINT TEST T .
Unable to duplicate the customer concern and no DTCs present	Refer to the Pinpoint Test	PINPOINT TEST H .
The HVAC functions are inoperative/do not operate correctly from touchscreen only	Communication network FDIM	REFER to INFORMATION AND ENTERTAINMENT SYSTEMS - 8-INCH (20 MM) TOUCHSCREEN, 10 SPEAKERS or INFORMATION AND ENTERTAINMENT SYSTEMS - THX 8-INCH (203 MM) TOUCHSCREEN, 16 SPEAKERS Symptom Chart and DIAGNOSE the touchscreen.
The air inlet door is inoperative	Refer to the Pinpoint Test	PINPOINT TEST I .
Incorrect/erratic direction of airflow from outlets	Refer to the Pinpoint Test	PINPOINT TEST J .
Reduced outlet airflow	Refer to the Pinpoint Test	If the A/C compressor does not cycle, PINPOINT TEST M . If the A/C compressor cycles normally, PINPOINT TEST R .
Insufficient, erratic or no heat	Refer to the Pinpoint Test	PINPOINT TEST K .
The A/C is inoperative	Refer to the Pinpoint Test	PINPOINT TEST L .
The A/C operation is erratic. The discharge air warms up when the vehicle comes to a stop.	Refer to the Pinpoint Test	DIAGNOSE all PCM DTCs before proceeding. REFER to the PCM DTC Chart . If no PCM DTCs are present PINPOINT TEST S .
The A/C is always on - A/C compressor does not cycle	Refer to the Pinpoint Test	PINPOINT TEST M .
The A/C is always on - A/C mode always commanded ON	Refer to the Pinpoint Test	PINPOINT TEST N .
Temperature control is inoperative/does not operate correctly	Refer to the Pinpoint Test	For driver side temperature concern, PINPOINT TEST O . For passenger side temperature concern, PINPOINT TEST P .
The blower motor is inoperative	Refer to the Pinpoint Test	PINPOINT TEST Q .
The blower motor does not operate correctly	Refer to the Pinpoint Test	PINPOINT TEST R .
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 SYSTEM . If the system pressure is above the A/C pressure relief valve open pressure, REPAIR the system for a restriction.