Fumes in Cab

I am experiencing fumes from other vehicles getting into my cab somehow. This is happening with my recirculation button activated on my AC control panel, and the windows fully closed of course. Are these trucks designed so that you will always have some kind of fresh air entering the vehicle, regardless if the recirculation button is activated or not?

 

Anyone...........

 

Is this a problem you just noticed occurring or has it always happened??

 

Pushing the button always solves it for me.
Maybe your button is not working?

 

A small amount of outside air will always be routed to the cab regardless of wether the recirc is on, even happen when the fan switch is off, fan still runs slowly.

 

On my first gen, if it is on the setting where it takes outside air in, and I have it completely off, a little bit of air will still be going in, so If i don't want any, ill switch it to the setting where it uses the Cab air and no more will come in.

 

I figured it would always allow a minimal amount of outside air in regardless of switch position. Thanks for the reasurance.........