The HVAC system is designed to blow air from either the floor, mid or defrost vents. In the following guide we will show you what to check for depending on the symptoms of the problem which is based on what you can hear, and feel.
When the HVAC system is on you should be able to hear the blower motor running,
this sound should change pitch when adjusting the fan speed. If no sound is heard
this means the blower motor is not working, start by testing the
relay, resistor or
blower motor itself.
If exact blower motor, fuse or relay locations are needed you can
ask our experts to supply you with the information
needed (free), or consult an online resource such as AllData DIY (pay).
If you can hear the blower fan working but still feel nothing from the vents,
or the vents are in the incorrect position this means the
mode blend door actuator is not
working correctly. This can sometimes be accompanied by a ticking noise which is
telling you the gears inside the actuator have failed. The actuator can be found
by flowing the noise, if no noise is heard the location is needed, again you can
ask one of our experts for help.
Some vehicles are equipped with a cabin air filter or Hepa filter which is designed
to clean the air in the HVAC system prior to exiting the vents. When this filter
clogs it hinders or stops the air flow supplied to the vents, to check the cabin
filter's condition locate the HVAC housing which can be either beneath the dash
or under the hood near the base of the windshield on the passenger side,
the cabin air filter to inspect and replace as needed. To find out if your vehicle
has one of these filters consult your owners manual or
ask one of our experts to help.
If just one vent is having problems check the flow control door that is located
at the vent outlet which is controlled by a thumb wheel that when activated, will
open and close the vent air flow door. Work the thumb wheel from side to side while
checking the airflow which should stop and start again. Sometimes these doors can
get stuck or broken which will block the air flow, in this case the vent will need
to be replaced.
There are two air intakes for the HVAC system, one is fresh air which is drawn in at the base of the windshield, the other is recirculated air which re-takes the air from inside the vehicle. If one of these intakes becomes clogged by a piece of paper, plastic bag or cloth or other form of blockage the air flow will stop. Locate the intakes and inspect for such items located at the base of the windshield (external), and at the passenger side footwell (internal).
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