AC/defrost not working properly

SNSHN1981

MEMBER
2008 MERCURY SABLE
3.5L
V6
2WD
AUTOMATIC
153,882 MILES

When I turn my car to defrost of floor vents there is no air that comes out. The air will come out of the dash vents. The system will make a clicking noise when the A/C is turned on. It has since I got the car in 2008. But just recently have I lost all of the defrost functions. Not sure where I would start to see where to find the problem and don’t want to take to a mechanic if it is something I could fix on my own. Also, when this happened, I lost the light behind my temperature and fuel level on my dash. Not sure if they are connected or not.

Thanks for any help.

7 Replies

SQM

MECHANIC
6,383 POSTS

Hello,

The air flow issue is likely due to a stuck mode door actuator. That actuator controls where the air will flow (floor, defrost, dash etc.).
As you can hear the clicking, it is likely the actuator making that noise as it's trying to switch positions but unable to.

There are two actuator one for the air inlet door (behind the glove box), other is the mode door (under the driver side dash).
Where do you hear the clicking noise coming from?

I have attached the replacement instructions for both.

Please let me know of any questions.
Thank you.

https://www.2carpros.com/articles/replace-blend-door-motor

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