Defrost only works with air recirculation off?

Am I doing something wrong? I finally had to use my defrost last weekend and when I turned it on it automatically switched to outside air. When I tried to switch it to inside (recirculated) air the defrost turned off. With wildfire smoke at dangerous levels on my drive over the mountains and the windshield fogging up as we drove it was frustrating to not be able to run inside air through the defrost to keep warm air moving across the windshield without choking ourselves on smoke. Is there a way to override this? I'm hoping it's pretty simple and my dumbass just needs to be led to it. Obviously the defrost works better if the recirc is off, but there are plenty of times when it's preferable to be running inside air for some other reason. Thanks!

 

I am sure somebody more versed will pop in and give you the correct answer (if mine is wrong...) but I am fairly certain that you cannot use the defrost function with recirc because the system needs to pull in fresh air thru the accumulator to rid it of the moisture/humidity. If you have the recirc on this doesn't happen and won't allow the windshield and other windows to defrost properly.

 

Pretty sure same is on older trucks too

 

I realize it will function better if it's not recirculating for the reason you mention, but there are times when outside air is a bad option and air across the windshield is still helpful even if it's not functioning 'properly' Sounds like that's not an option.

 

For some reason I think my '04 runs the defrost on both recirculated and outside air but it's been a bit since I've driven it so maybe I'm mistaken.

 

Defrost only works on vented air cycle not recirculate. Been this way for as long as I can remember but I’m only 41 years old.

 

I can concur with that. My '13 Tundra, '15 Grand Cherokee, and '22 Stelvio are all the same.

I first noticed this when I had an '04 4Runner, as soon as you switch to defog, the light for recirc goes off and the blend door opens.