All, I have a 2008 RDX that has recently stopped blowing air through the vents when switching from cold air to heat even though the air blend motor articulates just fine. With the AC on and set to low and the fan on high, air flows through the vent at normal levels. If I switch from cold to heat and the fan remains on high, the air stops flowing through the vents. When this happens it actually sounds like the air flow is being blocked. Any ideas would be helpful.

 

Hi! Welcome to the board. That sounds like a very annoying problem.

Just to clarify, no air comes out of your foot vents? All the vents, or just on one side? does the defrost vents work?

How did you determine that blend door motor is working properly? Did you physically look at it, or is it because it turns the face vents on and off?

 

Hi Daryl,

Thank you for your reply. When the temperature is set to low, air comes out of all vents. If the temp is set to high, all vents are blocked. I verified that the air mix motor is moving by crawling under the dash on the driver's side and observed the arm movement while changing the temp from low to high and back again.

 

It sounds like your cabin air filter is blocked. You should take it out and see if there are leaves or a scrap of paper blocking the air flow. It could also be that it needs to be changed.

One way to know for sure is to take the filter out TEMPORARILY (just for testing) and see if that resolves the issue.

Pretty easy, 3 minute test

But really, if you are going to do all the work to take the filter out, you should just replace it while you are in there