A/C System Symptom Diagnosis

Condition	Possible Cause	Action
No cool air comes out (A/C system does not operate)	No refrigerant	Perform recovery, evacuation an charge referring to OPERATION PROCEDURE FOR CHARGING A/C WITH REFRIGERANT .
	Fuse blown	Check related fuses, and then check for short circuit to ground .
	Evaporator temperature sensor faulty	Check evaporator temperature sensor referring to A/C EVAPORATOR TEMPERATURE SENSOR INSPECTION .
	A/C refrigerant pressure sensor faulty	Check A/C refrigerant pressure sensor referring to A/C REFRIGERANT PRESSURE SENSOR AND ITS CIRCUIT INSPECTION .
	Wiring or grounding faulty	Repair as necessary .
	ECT sensor faulty	Check ECT sensor referring to ECT (ENGINE COOLANT TEMPERATURE) SENSOR INSPECTION .
	ECM faulty	Check ECM referring to A/C SYSTEM INSPECTION AT ECM .
	HVAC control module faulty	Check HVAC control module referring to INSPECTION OF HVAC CONTROL MODULE AND ITS CIRCUITS .
	Magnet clutch faulty	Check magnet clutch referring to MAGNET CLUTCH OPERATING CHECK .
	Accessory (A/C compressor) drive belt loosened or broken	Replace drive belt and/or belt tensioner as necessary .
	Compressor faulty	Check compressor .
	Compressor relay faulty	Check compressor relay referring to A/C COMPRESSOR RELAY INSPECTION .
	Temperature selector, blower speed selector, and/or air flow selector faulty	Check HVAC control module referring to INSPECTION OF HVAC CONTROL MODULE AND ITS CIRCUITS .
	BCM faulty	Check BCM referring to INSPECTION OF BCM AND ITS CIRCUITS .
No cool air comes out (radiator cooling fan motor does not operate)	Fuse blown	Check related fuses, and then check for short circuit to ground .
	Wiring or grounding faulty	Repair as necessary .
	Radiator cooling fan motor relay faulty	Check radiator cooling fan motor relay referring to RADIATOR COOLING FAN RELAY INSPECTION .
	Radiator cooling fan motor faulty	Check radiator cooling fan motor referring to RADIATOR COOLING FAN RELAY INSPECTION .
	ECM faulty	Check ECM referring to A/C SYSTEM INSPECTION AT ECM .
	HVAC control module faulty	Check HVAC control module referring to INSPECTION OF HVAC CONTROL MODULE AND ITS CIRCUITS .
No cool air comes out (blower motor does not operate)	Fuse blown	Check related fuses, and then check for short circuit to ground .
	Blower motor controller faulty	Check blower motor controller referring to BLOWER MOTOR CONTROLLER INSPECTION .
	Blower speed selector faulty	Check blower speed selector referring to INSPECTION OF HVAC CONTROL MODULE AND ITS CIRCUITS .
	HVAC control module faulty	Check HVAC control module referring to INSPECTION OF HVAC CONTROL MODULE AND ITS CIRCUITS .
	Wiring or grounding faulty	Repair as necessary .
	Blower motor faulty	Check blower motor referring to BLOWER MOTOR INSPECTION .
	Blower motor relay faulty	Check blower motor relay referring to BLOWER MOTOR RELAY INSPECTION .
Cool air does not come out or insufficient cooling (A/C system normal operation)	Insufficient or excessive charge with refrigerant	Check the amount of refrigerant and system for leaks .
	Condenser clogged	Check condenser referring to A/C CONDENSER ASSEMBLY ON-VEHICLE INSPECTION .
	A/C evaporator clogged or frosted	Check A/C evaporator and evaporator temperature sensor referring to A/C EVAPORATOR INSPECTION and A/C EVAPORATOR TEMPERATURE SENSOR INSPECTION .
	Evaporator temperature sensor faulty	Check evaporator temperature sensor referring to A/C EVAPORATOR TEMPERATURE SENSOR INSPECTION .
	Expansion valve faulty	Check expansion valve referring to EXPANSION VALVE ON-VEHICLE INSPECTION .
	Desiccant clogged	Check desiccant .
	Accessory (A/C compressor) drive belt loosened or broken	Replace drive belt and/or belt tensioner as necessary .
	Magnet clutch faulty	Check magnet clutch referring to MAGNET CLUTCH OPERATING CHECK .
	Compressor faulty	Check compressor .
	Air in A/C system	Replace desiccant, and then perform evacuation and charge referring to OPERATION PROCEDURE FOR CHARGING A/C WITH REFRIGERANT .
	Air leaking from HVAC unit or air duct	Repair as necessary .
	Heater and ventilation system faulty	Check HVAC unit .
	Temperature selector faulty	Check temperature selector referring to INSPECTION OF HVAC CONTROL MODULE AND ITS CIRCUITS .
	HVAC control module faulty	Check HVAC control module referring to INSPECTION OF HVAC CONTROL MODULE AND ITS CIRCUITS .
	Temperature control actuator faulty	Check temperature control actuator referring to Temperature Control Actuator Inspection .
	Blower motor faulty	Check blower motor referring to BLOWER MOTOR INSPECTION .
	Excessive compressor oil in A/C system	Drain excessive compressor oil from A/C system circuit and compressor .
Cool air does not come out only intermittently	Wiring connection faulty	Repair as necessary .
	Expansion valve faulty	Check expansion valve referring to EXPANSION VALVE ON-VEHICLE INSPECTION .
	Excessive moisture in A/C system	Replace desiccant, and then perform evacuation and charge referring to OPERATION PROCEDURE FOR CHARGING A/C WITH REFRIGERANT .
	Magnet clutch faulty	Check magnet clutch referring to MAGNET CLUTCH OPERATING CHECK .
	Excessive amount of refrigerant	Check the amount of refrigerant .
Cool air comes out only at high speed	Condenser clogged	Check condenser referring to A/C CONDENSER ASSEMBLY ON-VEHICLE INSPECTION .
	Insufficient charge with refrigerant	Check the amount of refrigerant and system for leaks .
	Air in A/C system	Replace desiccant, and then perform evacuation and charge referring to OPERATION PROCEDURE FOR CHARGING A/C WITH REFRIGERANT .
	Accessory (A/C compressor) drive belt loosened or broken	Replace drive belt and/or belt tensioner as necessary .
	Compressor faulty	Check compressor .
Cool air does not come out only at high speed	Excessive amount of refrigerant	Check the amount of refrigerant .
Cool air does not come out only at high speed	A/C evaporator frosted	Check A/C evaporator and evaporator temperature sensor referring to A/C EVAPORATOR INSPECTION and A/C EVAPORATOR TEMPERATURE SENSOR INSPECTION .
Insufficient air flow of cooled air	A/C evaporator clogged or frosted	Check A/C evaporator and evaporator temperature sensor referring to A/C EVAPORATOR INSPECTION and A/C EVAPORATOR TEMPERATURE SENSOR INSPECTION .
	Air leaking from HVAC unit or air duct	Repair as necessary .
	Blower motor faulty	Check blower motor referring to BLOWER MOTOR INSPECTION Blower Motor Inspection .
	Wiring or grounding faulty	Repair as necessary .