My 2000 Saab 9-5 SE Wagon is blowing cold on the passenger side and warm(seems normal for the temp setting) on the driver side. Even the defroster is blowing colder on the right side than the left. It doesn't matter what I set the temp for on each side, the passenger side blows cold. It also blows cold in the rear of the car. Its been cold outside the last couple days so I can't tell you what it will blow like on a a warm day yet. Is it the control unit or the "air diverting mechanism" (not sure what the correct part is called) that opens and shuts the different vents? Any help would be greatly appreciated.