Symptom Chart - Climate Control Systems

WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. 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 the PCM DTC CHART .

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 PINPOINT TEST L: THE HVAC MODULE DOES NOT RESPOND TO THE SCAN TOOL .
Unable to duplicate the customer concern and no DTCs present	HVAC system and/or related components	GO to PINPOINT TEST K .
Reduced outlet airflow	Cabin air filter Air Conditioning Compressor Module (ACCM)	If the airflow is reduced only when in AUTO, A/C, MAX A/C, defrost or defrost/floor modes, GO to PINPOINT TEST P .
Reduced outlet airflow	Evaporator discharge air temperature sensor Blower motor Blower motor control PCM	If the airflow is reduced in all modes, INSPECT the cabin air filter. If the cabin air filter is clean and free of damage and debris, GO to PINPOINT TEST S .
The air inlet door is inoperative	Circuitry open/shorted Door actuator Air inlet door binding or stuck HVAC module	GO to PINPOINT TEST L .
Incorrect/erratic direction of airflow from outlets	Circuitry open/shorted Door actuator Mode door binding or stuck HVAC module	GO to PINPOINT TEST M .
Insufficient, erratic or no heat	Low engine coolant level 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 N .
The air conditioning (A/C) is inoperative	A/C pressure transducer Evaporator discharge temperature sensor HVAC module PCM Front Controls Interface Module (FCIM) Audio Control Module (ACM) ACCM	GO to PINPOINT TEST O .
The air conditioning (A/C) is always on	Evaporator discharge temperature sensor HVAC module PCM FCIM ACM ACCM	GO to PINPOINT TEST P .
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 Q .
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 R .
The blower motor does not operate correctly	Circuitry open/shorted A/C blower motor speed control HVAC module	GO to PINPOINT TEST S .
The temperature display will not switch between Celsius and Fahrenheit	HVAC module	INSTALL a new HVAC module. REFER to HEATING VENTILATION AIR CONDITIONING (HVAC) MODULE .
Inaccurate external temperature display	HVAC module Ambient temperature sensor	REFER to CLIMATE CONTROL SYSTEM .