There is a reason that you can not use recirculation in floor heat or defrost.

It's really all about the defrost.

When the heat is on the floor there is still some flow to the defrost to keep the windshield clear in cold weather.

If the system would allow recirculation on defrost it would take along time to defrost the windshield because the hvac system would not be able to vent out the moist air.

I had a customers car one time that the recirculation door was stuck closed. The windows in the car would take a very long time to clear and it never really cleared completely.

 

If you don't exhale, you don't need the A/C running in defrost.

 

You also don't need defrost if you remove the windshield and wear fog free goggles.

 

After this post, you won't have an excuse to not have an owner's manual. Download the PDF file for the year for your HHR and save it to your hard drive. You can also save the PDF to your smart phone and access it on the go.


Here are the manuals by year:


2006 - http://www.vadengmpp.com/owners-manu...vrolet-HHR.pdf


2007 -


2008 - https://www.chevrolet.com/content/da..._lt_owners.pdf


2009 - https://www.chevrolet.com/content/da...hhr_owners.pdf


2010 - https://www.chevrolet.com/content/da...hhr_owners.pdf


2011 - https://www.chevrolet.com/content/da...hhr_owners.pdf


I was not able to find a 2007 manual online.

 

Or, you could look at my sig and follow the link there!