Lexus Troubleshooting Questions? Ask a Lexus Expert
Hello and thank you for using just answer. A few questions to better help you here and narrow this down. First does the vent mode function work normally to cycle vent positions?
As far as the hot/cold issue does this symptom occur on both sides/zones of the vehicle or only the driver side? Do you hear any unusual noises such as clicking or grinding under the dash when you cycle from hot to cold?
By vent mode I mean position, there is a button on the climate control face plate that has controls vent postion (which vents the air comes out of).....face vents, floor vents, defrost or blended, was wanting to know if you can manually command the different vent positions.
By design you will always have some air coming out of the vents at road speed unless you manually command recirculation mode, the fresh air vents have air forced through the fresh air intake unless you seal it off by commanding recirculation.
If you cannot command heat/cold to operate then you need to start by inspecting the air mix servo motor under the dash to see if the servo motor is acting up or if this is an internal issue in the blower unit for the air mix door. It is somewhat common for the vent mode servo motors to fail on this vehicle but not as common for the air mix servo to fail. let me know if you would like some diagrams or further information on this.
Thank you for the reply, several items fo ryou then, you are dealing with an air mix servo issue, click these links for some help:
Check for codes and then for physical operation of the servo.
Sorry there is no easy way to get to this one, technically the manual is going to want you to pull the dash and the housing to service it out of car but with the right tools and patience you can better access this in the vehicle. If you have verified the servo does not respond then 1 of 3 issues: 1- bad servo 2- heat flap inside the housing is jammed and holding the servo in position 3- no power to the servo from the control head.
Note if you have an internal flap jam you should have at least a "twitching" action from the servo when commanded.