Blower motor air flow control

Im not sure about how ur lexus is set up, but the vehicles i have worked on, all of the doors in ur heat system, are ran off vacumn controls, i had one that was not working like that, would only blow air from the floor, well it turned out that one of the vacumn tubes got pinched off under a bolt, from a different repair, so somewhere to start. Im not sure if thats possible with what you had to do to replace ur switch, but if u had a lot of bolts to remove or somehow lines are pinched, that could be ur issue. Good luck.

I helped a co-worker with her 99's climate system. This is elaborate mechanically, accessed behind the glove box. The mode servo (floor/vent/defrost/mix), is likely, since air direction is the issue here. Lexus does not use vacuum lines, but electronics and motors to open and close those air doors. The servos run over $100, and while the repair is not difficult, access is, and quite involved. A Toyota dealer can repair it, or Toyota independent specialist, and for way less than a Lexus dealer.