Mr. FixIt: No Air is Blowing Through my Vents!

Have you ever gotten into your car on a hot summer day, eager to cool off with MAX COOL A/C, only to find there is no air coming through your vents?   (No cool air, no warm air….just literally NO air!)

This issue isn’t one which can be diagnosed without further exploration.  Components must be individually checked to arrive at the appropriate repair solution.  Some of these checks will require specific tools, training, or instruction.  Do not attempt to make repairs without proper tools and understanding.

(1) Your first check should be for a blown ventilation fuse.  A simple fuse replacement could give power back to the blower motor, and allow air to once again flow through the vents.  If this works, you’re finished!  If not, move on to #2

(2) Your cabin air filter removes debris from the outside air that is pumped into the cabin.   If the filter is clogged with contaminants, it may restrict air flow and your vents may blow little to no air.   An air filter change takes only a few minutes of your time.  If this solves your dilemma—great!  If not, forge ahead—bearing in mind the next options may require professional assistance if you are not a trained mechanic.

(3) Next check for damage to the blower motor.  The blower motor is a fan which pushes the cold (or hot) air through the cabin vents.  If it’s old or worn, it may cease functioning and fail to blow air into your cabin.  If it is still running properly, move along to check #4.  If it is not running properly, and you feel comfortable changing out this part you should do so.  Or, you can advise your technician that the blower motor or relay is not functioning.

(4) Your air conditioning system is equipped with many hoses and belts that engage and operate the system. Any sort of leak, detachment, tears or blockages will prevent proper airflow from the vents.  A thorough check might just uncover the root cause of your dilemma.

(5) Your final check should be the A/C clutch relay.   The relay transfers power, like a switch, from the interior controls to the compressor, engaging the compressor clutch.  A failed clutch relay can also cause a “no blow” situation since the relay takes the small electrical current and uses it to regulate the larger current needed for ventilation.  Locate the relay by tracing the wire connection from the A/C compressor plug-in to the relay.  It is usually mounted on the fender well or fire wall.  Testing the relay requires the use of an automotive circuit tester.

Summary:  There are some checks and repairs a person with mechanical aptitude can safely perform on his/her own. There may be others which require an A/C Technician to test and repair other ventilation system components. Repairs or replacement may be required.  Whether or not you are able to perform the complete repair yourself, this comprehensive checking routine may help you to diagnose the issue to more effectively communicate with your technician.

LMK 2021