Symptom Chart - Climate Control System

WARNING: This page is about a different car, the 2008 Mercury Mariner and 2008 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 Introduction - Gasoline Engines article.

Condition	Possible Sources	Action
No communication with the electronic automatic temperature control (EATC) or electronic manual temperature control (EMTC) module	Fuse(s) Circuitry open EATC or EMTC module communication network	REFER to MODULE COMMUNICATIONS NETWORK article.
The air inlet door is inoperative	Circuitry open/shorted Air inlet door actuator Air inlet door/linkage damaged, binding or stuck EMTC module or EATC module	Go to Pinpoint Test E .
Incorrect/erratic direction of airflow from outlets	Circuitry open/shorted Mode door actuator Mode door/linkage damaged, binding or stuck EMTC module or EATC module	Go to Pinpoint Test F .
The EATC system is inoperative, intermittent or incorrect operation	Fuse(s) Circuitry open EATC module	Go to Pinpoint Test G .
Insufficient, erratic or no heat	Low engine coolant level Plugged or partially plugged heater core Temperature blend door/actuator	Go to Pinpoint Test H .
The air conditioning (A/C) is inoperative/does not operate correctly	Fuse(s) Circuitry open A/C system discharged/low charge PCM EATC module EMTC module A/C clutch relay A/C low charge protection switch Dual-function pressure switch A/C compressor clutch air gap A/C clutch field coil	Go to Pinpoint Test I .
The air conditioning (A/C) is always on	Circuitry shorted PCM EATC module EMTC module A/C clutch relay A/C compressor clutch air gap A/C low charge protection switch	Go to Pinpoint Test J .
Temperature control is inoperative/does not operate correctly	Circuitry open/shorted EMTC module EATC module Temperature blend door is binding or stuck Temperature blend door actuator	Go to Pinpoint Test K .
The blower motor is inoperative - EMTC	Fuse(s) Circuitry open Blower motor switch Blower motor relay Blower motor EMTC module	Go to Pinpoint Test L .
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 M .
The blower motor is inoperative - EATC	Fuse(s) Circuitry short/open Blower motor relay Blower motor Blower motor speed control module EATC module	Go to Pinpoint Test N .
The blower motor does not operate correctly - EATC	Circuitry open/shorted Blower motor speed control module EATC module	Go to Pinpoint Test O .
The dual temperature control is inoperative/does not operate correctly	Temperature blend door/actuator broken/binding EATC module Low A/C refrigerant charge	Go to Pinpoint Test K .
The temperature set point does not repeat after turning the ignition switch OFF	Fuse Circuitry short/open EATC module	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 EATC module. REFER to CLIMATE CONTROL article. TEST the system for normal operation.
The temperature display will not switch between Celsius and Fahrenheit	EATC module Instrument cluster (IC) module	If the instrument cluster does not switch between English and Metric, REFER to INSTRUMENT CLUSTER AND PANEL ILLUMINATION article and diagnose. If only the EATC module does not switch between English and Metric, INSTALL a new EATC module. REFER to CLIMATE CONTROL article. TEST the system for normal operation.
Inaccurate external temperature display	EATC module Ambient temperature sensor	REFER to DESCRIPTION AND OPERATION of the EATC External Temperature Display. If the external temperature display is not operating as described and no DTC is present, CARRY OUT the Electronic Automatic Temperature Control (EATC) Module and Electronic Manual Temperature Control (EMTC) Module Cold Boot Process. If the conditions returns, INSTALL a new ambient temperature sensor. TEST the system for normal operation. If the condition returns again, INSTALL a new EATC module. REFER to CLIMATE CONTROL article. TEST the system for normal operation.