Symptom Chart - Climate Control Systems

WARNING: This page is about a different car, the 2012 Ford Flex. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Some PCM DTCs may inhibit A/C operation. If any PCM DTCs are retrieved, diagnose those first. Refer to INTRODUCTION - GASOLINE MODELS .

SYMPTOM CHART - CLIMATE CONTROL SYSTEMS

Condition	Possible Sources	Action
No communication with the HVAC module	Fuse(s) Circuitry open HVAC module communication network	REFER to MODULE COMMUNICATIONS NETWORK .
Unable to duplicate the customer concern and no DTCs present	HVAC system and/or related components	GO to Pinpoint Test I .
The air inlet door is inoperative	Circuitry open/shorted Door actuator Air inlet door binding or stuck HVAC module	GO to Pinpoint Test J .
Incorrect/erratic direction of airflow from outlets	Circuitry open/shorted Door actuator Mode door binding or stuck HVAC module	GO to Pinpoint Test K .
Reduced outlet airflow	Circuitry short A/C compressor clutch air gap	If the A/C compressor does not cycle, GO to Pinpoint Test N .
Reduced outlet airflow	A/C cycling switch A/C clutch relay Blower motor Blower motor control Blower motor resistor Blower motor switch PCM	If the A/C compressor cycles normally, GO to Pinpoint Test R .
Insufficient, erratic or no heat	Low engine coolant level Air in the cooling system Engine overheating Plugged or partially plugged heater core Temperature blend door is binding or stuck Temperature blend door actuator Heater hose is kinked or binding	GO to Pinpoint Test L .
The air conditioning (A/C) is inoperative	Fuse(s) Circuitry open A/C system discharged/low charge PCM HVAC module A/C clutch relay A/C compressor clutch air gap A/C pressure transducer Evaporator discharge temperature sensor A/C clutch field coil	GO to Pinpoint Test M .
The air conditioning (A/C) operation is erratic. The discharge air warms up when the vehicle comes to a stop.	Engine cooling fan relay Engine cooling fan PCM	DIAGNOSE all PCM DTCs before proceeding. REFER to the PCM DTC Chart .
		If no PCM DTCs are present GO to Pinpoint Test Y .
The air conditioning (A/C) is always on - A/C compressor does not cycle	Circuitry shorted PCM A/C clutch relay A/C compressor clutch air gap A/C pressure transducer A/C clutch field coil	GO to Pinpoint Test N .
The air conditioning (A/C) is always on - A/C mode always commanded ON	Circuitry shorted PCM HVAC module	GO to Pinpoint Test O .
Temperature control is inoperative/does not operate correctly	Circuitry open/shorted HVAC module Temperature blend door is binding or stuck Temperature blend door actuator	GO to Pinpoint Test P .
The blower motor is inoperative	Fuse(s) Circuitry short/open Blower motor relay A/C blower motor HVAC module A/C blower motor speed control	GO to Pinpoint Test Q .
The blower motor does not operate correctly	Circuitry open/shorted A/C blower motor speed control HVAC module	GO to Pinpoint Test R .
The auxiliary blower motor is inoperative	Fuse(s) Circuitry open Auxiliary blower motor relay Auxiliary blower motor speed control Auxiliary blower motor HVAC module	GO to Pinpoint Test S .
The auxiliary blower motor does not operate correctly	Fuse(s) Circuitry open/shorted Auxiliary blower motor relay Auxiliary blower motor speed control	If the auxiliary blower motor does not operate correctly from both the front and rear auxiliary controls, GO to Pinpoint Test T .
	Rear auxiliary control HVAC module	If the auxiliary blower motor does not operate correctly from the rear auxiliary controls only, GO to Pinpoint Test W .
		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	Circuitry open/shorted Auxiliary blend door actuator HVAC module	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, GO to Pinpoint Test W .
		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	Circuitry open/shorted Auxiliary mode door actuator HVAC module	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, GO to Pinpoint Test W .
		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 or blower motor controls are inoperative/do not operate correctly using the rear auxiliary climate controls only	Circuitry open/shorted Rear auxiliary control HVAC module	GO to Pinpoint Test W .
The temperature set point does not repeat after turning the ignition switch OFF	HVAC module	INSTALL a new HVAC module. REFER to CLIMATE CONTROL . TEST the system for normal operation.
The temperature display will not switch between Celsius and Fahrenheit	HVAC module	INSTALL a new HVAC module. REFER to CLIMATE CONTROL . TEST the system for normal operation.
Inaccurate external temperature display	HVAC module Ambient temperature sensor	REFER to Description and Operation of the HVAC module external temperature display. If the external temperature display is not operating as described and no DTC is present, CARRY OUT the Ambient Temperature Sensor component test . If the sensor tests OK, INSTALL a new HVAC module. REFER to 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, REPLACE the A/C pressure relief valve. If the system pressure is above the A/C pressure relief valve open pressure, REPAIR the system for a restriction.