Why no recirc with defog/defrost?

[tarhicks]

New kid on the block here. I just bought an 08 Vibe and am working through the differences from what I expected after two Saturn sedans. So... why doesn't the recirc work with defog/defrost? At first I thought it was broken, but then I read in the manual that is the way it standardly works. But why? Does anyone know? I hate being stopped by a stinky car and needing to defrost at the same time. Thanks for all the good info here!

[ColonelPanic]

When you're using defrost and have recirculate on, it actually tends to make fogging much worse. Recirculated air will have a much higher humidity content than what the fresh outside air would have. IIRC, you should still be able to put it in recirculate after you move the knob to the defrost. You just can't have recirc on when you move the knob to defrost since the mechanical link between the mode knob and recirc button will kick off the recirculate.

[chevelle_lover]

Forgive me for asking but does it not use the defrost vents as an intake when using the recircluate on the HVAC.

[star_deceiver]

There is an opening by the blower that acts to recurculate the air.And yes, +1 on fogging up with recirc engaged!