Symptom Troubleshooting Index

TROUBLESHOOTING CHART

Symptom	Diagnostic procedure	Also check for
The blower and heater controls and the A/C system do not work	Probable cause: Climate control unit malfunction Do the Climate Control Power and Ground Circuit Troubleshooting (see CLIMATE CONTROL POWER AND GROUND CIRCUIT TROUBLESHOOTING )	HVAC DTCs (see GENERAL TROUBLESHOOTING INFORMATION ) Blown fuse No. 30 (10 A) in the under-dash fuse/relay box Faulty blower motor relay Poor ground at G402 (see DASHBOARD WIRE HARNESS (RIGHT BRANCH) ) 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 switch circuit malfunction Do the A/C Pressure Switch Circuit Troubleshooting (see A/C PRESSURE SWITCH CIRCUIT TROUBLESHOOTING )	HVAC DTCs (see GENERAL TROUBLESHOOTING INFORMATION ) Powertrain DTCs (see GENERAL TROUBLESHOOTING INFORMATION ) Body DTCs in B-CAN system (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ) Poor or loose connections at the terminals
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 )	HVAC DTCs (see GENERAL TROUBLESHOOTING INFORMATION ) Blown fuse No. 12 (7.5 A) in the under-hood fuse/relay box Poor or loose connections at the terminals
Voice commands do not work	Probable cause: Communication problem between the climate control unit and the navigation system Do the Navigation Communication Line Circuit Troubleshooting (see NAVIGATION COMMUNICATION LINE CIRCUIT TROUBLESHOOTING )	HVAC DTCs (see GENERAL TROUBLESHOOTING INFORMATION ) Poor or loose connections at the terminals
Driver's and passenger's side vent temperatures vary by more than 20 °F (11 °C)	Probable causes: The recirculation control door or an air mix door is malfunctioning Do the following troubleshooting: Recirculation Control Motor Circuit Troubleshooting (see RECIRCULATION CONTROL MOTOR CIRCUIT TROUBLESHOOTING ) Driver's Air Mix Control Motor Test (see DRIVER'S AIR MIX CONTROL MOTOR TEST ) Passenger's Air Mix Control Motor Test (see PASSENGER'S AIR MIX CONTROL MOTOR TEST )	HVAC DTCs (see GENERAL TROUBLESHOOTING INFORMATION ) 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 the ECT sensor circuit: ECT sensor 2 circuit low voltage (see DTC P2184: ECT SENSOR 2 CIRCUIT LOW VOLTAGE ) ECT sensor 2 circuit high voltage (see DTC P2185: ECT SENSOR 2 CIRCUIT HIGH VOLTAGE )	HVAC DTCs (see GENERAL TROUBLESHOOTING INFORMATION ) Powertrain DTCs (see GENERAL TROUBLESHOOTING INFORMATION ) Blower motor operation
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 Do the Driver's Air Mix Control Motor Test (see DRIVER'S AIR MIX CONTROL MOTOR TEST ) and Passenger's Air Mix Control Motor Test (see PASSENGER'S AIR MIX CONTROL MOTOR TEST ) Check the blower motor unit for obstructions Check for air leaks around the ducts and vents	HVAC DTCs (see GENERAL TROUBLESHOOTING INFORMATION ) Damaged cylinder head gasket
NOTE: For symptoms not described here, refer to the Heating/Air Conditioning Troubleshooting Index.