I need to fix the air flow mixer in the dash of a 97 SSE. I have had this happen before on a different bonneville, but did not attempt to fix it myself. I am going to tackle this in the near future as the air flow only comes out the floorboard or defroster at the same time. I can find no vacuum leaks so I am assuming that the dash needs to come apart to get to the parts inside there. Anyone have any suggestions or pointers on how to do this and how long it should take? Thanks in advance for any input on this.