Heater And Ventilation Symptom Diagnosis

HEATER AND VENTILATION DIAGNOSTIC CHART

Condition	Possible Cause	Action
Blower won't work even when blower speed selector is ON	Blower fuse blown	Replace fuse to check for short .
	Blower motor faulty	Check blower motor referring to BLOWER MOTOR INSPECTION .
	Blower motor relay faulty	Check relay referring to BLOWER MOTOR RELAY INSPECTION .
	Blower motor controller faulty	Check blower motor controller referring to BLOWER MOTOR CONTROLLER INSPECTION .
	Blower speed selector faulty	Check HVAC control module referring to HVAC CONTROL MODULE AND ITS CIRCUITS INSPECTION (FOR VEHICLE WITHOUT A/C) or HVAC CONTROL MODULE AND ITS CIRCUITS INSPECTION .
	Wiring or grounding faulty	Repair as necessary .
Air temperature is not changed even when temperature selector is changed	Temperature control door broken	Repair Temperature control door .
	Linkage broken	Check actuator linkage referring to ACTUATOR LINKAGE INSPECTION .
	Heater hoses leaking or clogged	Replace hoses .
	Heater core leaking or clogged	Replace heater core referring to HEATER CORE REMOVAL AND INSTALLATION .
	Temperature control actuator faulty	Check temperature control actuator referring to TEMPERATURE CONTROL ACTUATOR INSPECTION .
	Temperature selector faulty	Check HVAC control module referring to HVAC CONTROL MODULE AND ITS CIRCUITS INSPECTION (FOR VEHICLE WITHOUT A/C) (for Vehicle without A/C) or HVAC CONTROL MODULE AND ITS CIRCUITS INSPECTION (FOR VEHICLE WITHOUT A/C) .
Air outlet port is not changed when air flow selector is changed	Air flow control door broken	Repair air flow control door .
	Linkage broken	Check actuator linkage referring to ACTUATOR LINKAGE INSPECTION .
	Air flow control actuator faulty	Check air flow control actuator referring to AIR FLOW CONTROL ACTUATOR INSPECTION .
	Mode selector faulty	Check HVAC control module referring to HVAC CONTROL MODULE AND ITS CIRCUITS INSPECTION (FOR VEHICLE WITHOUT A/C) (for Vehicle without A/C) or HVAC CONTROL MODULE AND ITS CIRCUITS INSPECTION (FOR VEHICLE WITHOUT A/C) .
No fresh air inlet is changed .	Fuse blown	Check related fuses and check for short circuit to ground .
	Air intake control actuator faulty	Check air intake control actuator .
	Air intake control door broken	Repair air intake control door .
	Linkage broken	Check actuator linkage referring to ACTUATOR LINKAGE INSPECTION .
	Air intake selector faulty	Check HVAC Control module referring to HVAC CONTROL MODULE AND ITS CIRCUITS INSPECTION (FOR VEHICLE WITHOUT A/C) (for Vehicle without A/C) or HVAC CONTROL MODULE AND ITS CIRCUITS INSPECTION (FOR VEHICLE WITHOUT A/C) .
	Wiring or grounding faulty	Repair or replace as necessary .