Symptom Troubleshooting Index

Symptom	Diagnostic procedure	Also check for
The blower and heater controls and the A/C system do not work	Probable cause: The climate control unit has malfunctioned, or has lost power or ground. Do the climate control power and ground circuit troubleshooting (see CLIMATE CONTROL POWER AND GROUND CIRCUIT TROUBLESHOOTING )	Climate control DTCs (see HOW TO CHECK FOR DTCS WITH THE HDS ) Blown fuse No. 16 (7.5 A) in the driver's under-dash fuse/relay box Poor ground at G403 (see CONNECTOR TO FUSE/RELAY BOX INDEX ) Poor or loose connections at the terminals
The A/C compressor clutch and the A/C condenser/radiator fans are inoperative, but the blower and heater controls work	Probable cause: A/C pressure sensor circuit malfunction. NOTE: When the A/C pressure sensor malfunctions, it may or may not set a DTC	Climate control DTCs (see HOW TO CHECK FOR DTCS WITH THE HDS ) Powertrain DTCs Poor or loose connections at the terminals A/C signal circuit problem in the PCM (see A/C SIGNAL CIRCUIT TROUBLESHOOTING ) Check sensor input display mode (see RUN THE SENSOR INPUT DISPLAY MODE ): Sensor #5 Evaporator Sensor #9 A/C Pressure
The A/C compressor clutch does not engage, but the A/C condenser/radiator fans operate, and the blower and heater controls work	Probable cause: No power to the A/C compressor clutch Do the A/C compressor clutch circuit troubleshooting (see A/C COMPRESSOR CLUTCH CIRCUIT TROUBLESHOOTING ) Low speed idle High engine coolant temperature (ECT) Do the evaporator temperature sensor test (see EVAPORATOR TEMPERATURE SENSOR TEST )	Climate control DTCs (see HOW TO CHECK FOR DTCS WITH THE HDS ) Powertrain DTCs Blown fuse No. 20 (7.5 A) in the under-hood fuse/relay box A/C system pressure is normal (see SYSTEM DESCRIPTION ) Poor or loose connections at the terminals
The A/C condenser fan and/or the radiator fan do not run with the A/C on	Probable cause: A/C condenser/radiator fan low speed circuit malfunction. Do the radiator and A/C condenser fan low speed circuit troubleshooting (see RADIATOR AND A/C CONDENSER FAN LOW SPEED CIRCUIT TROUBLESHOOTING )	Climate control DTCs (see HOW TO CHECK FOR DTCS WITH THE HDS ) Powertrain DTCs Blown fuse No. 3-2 (SUB FAN MOTOR) (40 A) Poor ground at G301 (see CONNECTOR TO FUSE/RELAY BOX INDEX ) Poor or loose connections at the terminals
The A/C condenser/radiator fans do not run at high speed, but do run at low speed	Probable cause: Malfunction in the fan high speed circuit(s). Do the following troubleshooting as needed: A/C condenser fan high speed circuit troubleshooting (see A/C CONDENSER FAN HIGH SPEED CIRCUIT TROUBLESHOOTING ) Radiator fan high speed circuit troubleshooting (see RADIATOR FAN HIGH SPEED CIRCUIT TROUBLESHOOTING )	Climate control DTCs (see HOW TO CHECK FOR DTCS WITH THE HDS ) Powertrain DTCs Blown fuse No. 3-2 (SUB FAN MOTOR) (40 A) and No. 3-5 (MAIN FAN MOTOR) (40 A) Poor ground at G202 (see CONNECTOR TO FUSE/RELAY BOX INDEX ) Poor or loose connections at the terminals
Voice commands do not work	Probable cause: Communication problem between the climate control unit and the audio-navigation unit. Do the navigation communication line circuit troubleshooting (see NAVIGATION COMMUNICATION LINE CIRCUIT TROUBLESHOOTING )	Climate control DTCs (see HOW TO CHECK FOR DTCS WITH THE HDS ) Navigation unit DTCs (see HOW TO CHECK ERROR HISTORY (NAVIGATION DTCS) ) Poor or loose connections at the terminals
The climate control display is inoperative	Probable cause: Communication problem between the climate control unit and the audio-navigation and HVAC switch panel (with navigation) or the audio and HVAC switch panel (without navigation). Do the HVAC communication line circuit troubleshooting; with navigation (see HVAC COMMUNICATION LINE CIRCUIT TROUBLESHOOTING ), without navigation (see WITHOUT NAVIGATION )	Climate control DTCs (see HOW TO CHECK FOR DTCS WITH THE HDS ) HVAC display failure Poor or loose connections at the terminals
The climate control switches do not work	Probable cause: Climate control switch communication line circuit malfunction. Do the HVAC switch communication line circuit troubleshooting; with navigation (see WITH NAVIGATION ), without navigation (see WITHOUT NAVIGATION )	Climate control DTCs (see HOW TO CHECK FOR DTCS WITH THE HDS ) Poor or loose connections at the terminals
Blower fan runs slower than expected in cold weather (when in AUTO mode) NOTE: It is normal for the blower fan to run slowly until the coolant temperature rises when in AUTO mode	Probable cause: Engine coolant temperature (ECT) circuit malfunction. Troubleshoot ECT Sensor 2 Circuit Range/Performance Problem (see DTC P2183: ECT SENSOR 2 CIRCUIT RANGE/PERFORMANCE PROBLEM )	Climate control DTCs (see HOW TO CHECK FOR DTCS WITH THE HDS ) Powertrain DTCs Manual blower motor operation Engine thermostat
The A/C compressor clutch cycles rapidly on and off	Probable cause: A/C system is very low on refrigerant, indicating a possible leak. Do the refrigerant leak check (see REFRIGERANT LEAK CHECK ) and repair any leaks. Evaporator temperature sensor test (see EVAPORATOR TEMPERATURE SENSOR TEST )	Climate control DTCs (see HOW TO CHECK FOR DTCS WITH THE HDS ) If there is no leak and the refrigerant level is normal, do the A/C compressor clutch circuit troubleshooting (see A/C COMPRESSOR CLUTCH CIRCUIT TROUBLESHOOTING ), and look for an intermittent problem Low idle ECT
The A/C compressor clutch does not disengage when the A/C switch is off	Probable cause: The A/C compressor clutch circuit is on (energized) continuously, shorted to ground, stuck A/C compressor clutch relay, or the A/C compressor clutch is mechanically jammed Do the A/C compressor clutch circuit troubleshooting (see A/C COMPRESSOR CLUTCH CIRCUIT TROUBLESHOOTING ), and repair any circuit problems If the A/C compressor clutch circuit is OK, then do the A/C compressor clutch check (see A/C COMPRESSOR CLUTCH CHECK ), and repair any problems with the A/C compressor clutch	The A/C compressor relief valve. If it has vented refrigerant to the atmosphere, correct the problem with the A/C compressor clutch or clutch circuit, then replace the relief valve (see A/C COMPRESSOR RELIEF VALVE REPLACEMENT )
The A/C compressor relief valve has vented refrigerant NOTE: This indicates the A/C system pressure was very high	Probable cause: A high-side restriction, the A/C condenser/radiator fans are inoperative, or the A/C compressor clutch is not disengaging If the fans and A/C compressor clutch operate normally, recover refrigerant (see REFRIGERANT RECOVERY ), and check for restrictions If the A/C compressor clutch will not disengage, troubleshoot the A/C compressor clutch circuit (see A/C COMPRESSOR CLUTCH CIRCUIT TROUBLESHOOTING ), and check for mechanical problems (see RECIRCULATION CONTROL MOTOR TEST ) If the fans are inoperative, troubleshoot the fan circuits (see RADIATOR AND A/C CONDENSER FAN LOW SPEED CIRCUIT TROUBLESHOOTING )	Powertrain DTCs
HDS does not communicate with the climate control unit or the vehicle	Troubleshoot the DLC circuit (see DLC CIRCUIT TROUBLESHOOTING )
Insufficient heating	Check the coolant level (see COOLANT CHECK ) Check the radiator cap (see RADIATOR CAP TEST ) Check the coolant temperature during normal operation Check the heater core inlet hose temperature: If it is COLD, check for restrictions in the hose, a damaged or leaking thermostat, or a damaged or leaking water pump If it is HOT, check for restrictions in the heater core. Back flush or replace the heater core. Check the operation of the air mix doors: Driver's (see DRIVER'S AIR MIX CONTROL MOTOR TEST ) Passenger's (see PASSENGER'S AIR MIX CONTROL MOTOR TEST ) Check the blower motor unit for obstructions Check for air leaks around the ducts and vents	Climate control DTCs (see HOW TO CHECK FOR DTCS WITH THE HDS ) Damaged cylinder head gasket