There is a recirculation air setting for the interior (its the sideways U with the arrow) in the climate control panel. I normally drive with the air setting in recirculation mode to avoid inhaling exhaust from cars in front. I've noticed that recently the recirculation setting changes (without me changing it) to non-recirculation of air (i.e. getting air from the exterior). Is this suppose to happen or does the closed vent flap open because of vibration or external air pressure? Thanks Dave
On my 2004, if the defrost is on when I turn the car off, the air source setting changes itself to external when I turn the car on again. Very annoying. Perhaps it does this in other circumstances also.
I hunch the air conditioning (cooling, heating, defrosting...) system is just trying to be efficient. If the air outside is cooler, it will choose to bring some of that inside, rather than cooling the air that's already there. I much prefer mostly outside air, as it keeps me more alert on long trips.
The A/C system tries to regulate humidity as well as temperature. It will bring outside air in to keep the humidity from building up, and to prevent the windows from frosting inside.
'Tries' being the operative word. Around here, the humidity is sometimes so high we need personal flotation devices to leave the house. Any idea if there's an external humidity sensor?
