So i noticed this, everytime i am about to be in a underground tunnel, i hit the recirculate button, but by the end of the tunnel, i'm sucking in exhaust fumes because it turned itself off.

does anyone have this issue? i have the issue regardless of whether A/C is on. it seems to turn itself off after a few minutes. The feature itself does work, when it is recirculating, i do not smell the exhaust fumes in the car that i am following.

 

It does it automatically if the vent is set on floor, defrost, or floor and dash vent. The only one it will stay on recirc is dash only. It's the way it is designed. Honda is the same.

 

Thanks! going to give that a try later, getting sick of eating exhaust from trucks that should not pass inspections!