How do you replace windshield on a 2002 Kia Spectra?

It could possibly be a bad vacuum line connection. some cars use a vacuum powered motor to divert the air to different vents when you select them on the climate controls. With the car running, open the hood and listen for any hissing noises, like leaking air.If you dont find any leaks there, and you don't hear a hissing inside the car, you may possibly have bad ductwork in your car. if you find a vacuum leak,either replace the hose, or sometimes it iis as simple as pushing the hose back onto a fitting.