BMW Repair: Air condition, center vents, bmw 325 i

Question
2002 BMW 325 I, (Pennsylvania USA) The air conditioner will work fine , going down the road it will suddenly blow warm to hot air from center dash vents and cold on outside vents. If the 3 control buttons are pushed , hot air will come from the floor or defroster area.The outside dash vents continue to blow cool air.Could this be a coolant problem? Or something way more involved.

Answer
Not familiar with this model, but the center vents are usually separately controllable, and are more direct outside air.  Do you have these set to cold?

I don't understand how you can be getting hot air from the floor and defroster, while cold air from the side (outside) vents.

If everything is set fine, you may have a problem with the damper controls.

Have you had the car long?  Is this something that just started?  Or is it a newer car for you?