i have closed the Air control heater valve,the air is cold now,,,and the heater shutter has been closed ,,,the fresh air is not coming through the vents,,,, now i wana learn about the MODE control,,caz the AC vents are not blowing the air like they shud be,,,, the outer AC vents are blowing enough air,,but the center ones are too slow,,,how to change the mode of AC? caz the AC Mode motor under the dash is also not working,,any advise please?