Symptom Chart - Climate Control System

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 PCM DTC CHART .

SYMPTOM CHART - CLIMATE CONTROL SYSTEM

Condition	Possible Sources	Action
No communication with the HVAC module - Dual Automatic Temperature Control (DATC) or HVAC module - Electronic Manual Temperature Control (EMTC)	Fuse(s) Circuitry open HVAC module - DATC or HVAC module - EMTC 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 G .
Reduced outlet airflow	Circuitry short A/C compressor clutch air gap 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 does not cycle, GO to PINPOINT TEST L . EMTC systems, If the A/C compressor cycles normally, GO to PINPOINT TEST P . DATC systems, If the A/C compressor cycles normally, GO to PINPOINT TEST R .
The air inlet door is inoperative	Circuitry open/shorted Air inlet door actuator Air inlet door/linkage damaged, binding or stuck HVAC module - EMTC or HVAC module - DATC	GO to PINPOINT TEST H .
Incorrect/erratic direction of airflow from outlets	Circuitry open/shorted Mode door actuator Mode door/linkage damaged, binding or stuck HVAC module - EMTC or HVAC module - DATC	GO to PINPOINT TEST I .
Insufficient, erratic or no heat	Low engine coolant level Plugged or partially plugged heater core Temperature blend door/actuator	GO to PINPOINT TEST J .
The air conditioning (A/C) is inoperative	Fuse(s) Circuitry open A/C system discharged/low charge PCM HVAC module - DATC HVAC module - EMTC A/C clutch relay A/C compressor clutch air gap A/C clutch field coil	GO to PINPOINT TEST K .
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 low charge protection switch	GO to PINPOINT TEST L .
The air conditioning (A/C) is always on - A/C mode always commanded ON	Circuitry shorted PCM HVAC module - DATC HVAC module - EMTC	GO to PINPOINT TEST M .
Temperature control is inoperative/does not operate correctly	Circuitry open/shorted HVAC module - EMTC HVAC module - DATC Temperature blend door is binding or stuck Temperature blend door actuator	GO to PINPOINT TEST N .
The blower motor is inoperative - EMTC	Fuse(s) Circuitry open Blower motor switch Blower motor relay Blower motor HVAC module - EMTC	GO to PINPOINT TEST O .
The blower motor does not operate correctly - EMTC	Circuitry open/shorted A/C blower motor resistor A/C blower motor switch	GO to PINPOINT TEST P .
The blower motor is inoperative - DATC	Fuse(s) Circuitry short/open Blower motor relay Blower motor Blower motor speed control module HVAC module - DATC	GO to PINPOINT TEST Q .
The blower motor does not operate correctly - DATC	Circuitry open/shorted Blower motor speed control module HVAC module - DATC	GO to PINPOINT TEST R .
The dual temperature control is inoperative/does not operate correctly	Temperature blend door/actuator broken/binding HVAC module - DATC Low A/C refrigerant charge	GO to PINPOINT TEST N .
The temperature set point does not repeat after turning the ignition switch OFF	Fuse Circuitry short/open HVAC module - DATC	VERIFY Smart Junction Box (SJB) fuse 15 (10A) is OK. If OK, CHECK circuit SBP15 (WH/RD) for a short or open and REPAIR as necessary. TEST the system for normal operation. If OK, 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 - DATC Instrument Cluster (IC)	If the IC does not switch between English and Metric, REFER to INSTRUMENT CLUSTER AND PANEL ILLUMINATION and diagnose. If only the HVAC module - DATC does not switch between English and Metric, INSTALL a new HVAC module. REFER to CLIMATE CONTROL . TEST the system for normal operation.
Inaccurate external temperature display	HVAC module - DATC Ambient temperature sensor	REFER to DESCRIPTION AND OPERATION of the HVAC module - DATC External Temperature Display. If the external temperature display is not operating as described and no DTC is present, INSTALL a new ambient temperature sensor. TEST the system for normal operation. If the condition returns again, INSTALL a new HVAC module. REFER to CLIMATE CONTROL . TEST the system for normal operation.