Hi, I have a 2010, F-150, Lariat that is taking in outside air no matter what. I engage the recirculate air mode, but can still smell exhaust smell coming from cars in front. Also, when I turn off the A/C system all together, I can still feel air coming through vents. Any idea what is causing this? I'm assuming some sort of flapper or diversion vent, but have no idea where to start.

 

I imagine the blend doors are not perfect seals. Even when mine is in recirc, I can still smell outside air. Also, if you have your climate control on Auto, shutting off the A/C won't necessarily shut off the entire system. Even when mine reaches the set temperature, the fan still runs, albeit very slowly.

 

Got it. I don't think I've ever used the auto function and I'm still having air filter in through the vents with the entire system off. Either way, I'm guessing this isn't something that can be fixed with minimal effort. I should probably take this to a mechanic to have them look at it.