HVAC System Symptom Diagnosis: Notes

WARNING: This page is about a different car, the 2010 Suzuki Kizashi. However, it is still accessible from the selected car via links, so may be relevant.

HVAC SYSTEM SYMPTOM DIAGNOSIS CHART

Condition	Possible Cause	Action
Blower motor does not operate	Blown fuse	Check related fuses, and then check for short circuit to ground .
	Faulty blower motor relay	Check blower motor relay.
	Faulty blower motor controller	Check blower motor controller.
	Faulty blower motor	Check blower motor.
	Faulty wiring or grounding	Repair wiring .
	Faulty HVAC control module	Check HVAC control module.
	Foreign material is present	Remove foreign material .
No cool air comes out (A/C system does not operate)	No refrigerant	Perform RECOVERY , EVACUATION and CHARGE .
	Blown fuse	Check related fuses, and then check for short circuit to ground .
	Faulty evaporator temperature sensor	Check evaporator temperature sensor.
	Faulty A/C refrigerant pressure sensor	Check A/C refrigerant pressure sensor.
	Faulty wiring or grounding	Repair wiring .
	Faulty ECT sensor	Check ECT sensor.
	Faulty ECM	Check ECM.
	Faulty HVAC control module	Check HVAC control module.
	Faulty magnet clutch	Check magnet clutch.
	Loosened or broken accessory (A/C compressor) drive belt	Replace drive belt and/or belt tensioner if necessary .
	Faulty A/C compressor	Check A/C compressor .
	Faulty A/C compressor relay	Check A/C compressor relay.
	Faulty auto A/C panel	Replace auto A/C panel .
	Faulty BCM	Check BCM.
No cool air comes out (blower motor does not operate)	Blown fuse	Check related fuses, and then check for short circuit to ground .
	Faulty blower motor controller	Check blower motor controller.
	Faulty HVAC control module	Check HVAC control module.
	Faulty wiring or grounding	Repair wiring .
	Faulty blower motor	Check blower motor.
	Faulty blower motor relay	Check blower motor relay.
Cool air does not come out or insufficient cooling	Insufficient or excessive charge of refrigerant	Check the amount of refrigerant and system for leaks .
	Clogged condenser	Check condenser.
	Clogged or frosted evaporator	Check evaporator and evaporator temperature sensor . Evaporator Evaporator temperature sensor
	Faulty evaporator temperature sensor	Check evaporator temperature sensor.
	Faulty A/C refrigerant pressure sensor	Check A/C refrigerant pressure sensor.
	Faulty ECM	Check ECM.
	Faulty BCM	Check BCM.
	Faulty expansion valve	Check expansion valve.
	Clogged desiccant	Check desiccant .
	Accessory (A/C compressor) drive belt loosened or broken	Replace drive belt and/or belt tensioner if necessary .
	Faulty magnet clutch	Check magnet clutch.
	Faulty A/C compressor	Check A/C compressor .
	Air in A/C system	Replace desiccant, and then perform EVACUATION and CHARGE .
	Air leaking from HVAC unit or air duct	Repair if necessary .
	Faulty heater and ventilation system	Check HVAC unit .
	Faulty auto A/C panel	Replace auto A/C panel .
	Faulty HVAC control module	Check HVAC control module.
	Faulty temperature control actuator	Check temperature control actuator.
	Faulty wiring or grounding	Repair if necessary .