Blower motor air flow control


Asked by Jlanning13 Nov 17, 2012 at 03:16 AM about the 1999 Lexus RX 300 Base AWD

Question type: Maintenance & Repair

I replaced my blower motor controller today.  The air conditioner and heat is now blowing, but only from below where the feet vents are, there is no air flowing to the dash or vents by the windshield. I am unable to control the airflow.  I can control the air speed via the mode control knob, but not where it is going. I am unable to change the area to which it is to flow.  The arrows do change to different areas being the feet, chest, or windshield or both pertaining to the stick figure via the control knob showing where the air is to go, but it doesn't actually change levels or vents.  Also I see a site on the internet for a chip that is available to increase my gas mileage by 7 mpg's and slight increase in horsepower.  Is this true for the price of $65 per chip or will it cause issues with my fuel injection or other problems.

2 Answers


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.

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