2000 Lexus GS300 Dual Climate Actuator Repair

My parent's old Lexus was blowing heat out of the passenger side even when set to full A/C "Cold" mode.  The repair was pretty simple.  The temperature is controlled by a set of doors that mix air coming across the heater core with air coming across the evaporator core.  The doors are controlled by actuators with built in position sensors.  To access the actuator, remove the footwell trim panel, open up the glove box, remove the glovebox by removing the screws, disconnecting the light bulb, and detaching the yellow air bag wire from the assembly.  Next remove the CD changer.

Trim Panel

Glove Box

Release Light and Harness

Remove the CD Changer

Next, you need to get the air duct out of the way.  Remove the retention screws and pull the duct out the car.

Once the air duct is out you have access to the actuator.

The passenger side mix door actuator can be seen here to the left of the heater tubes.

Passenger side mix door actuator can be seen by looking to the left of the heater tubes and
locating the yellow bushing partially obscured by the large white air duct.

The actuator is held in place with three screws.  I had to pull the heater tubes slightly to the side to access one of the screws.

Once the actuator was out I decided to try and repair it before buying a new one.  I opened the case by gently prying open the side latches (be careful, I broke a couple of tabs) and cleaned the resistive position sensing traces on the back side of the main gear.  I soaked q-tips in alcohol then held them against the underside of the large gear while spinning it around.  After several q-tips the residue eventually stopped coming off.  Now that the sensing traces were clean I used another q-tip to pick up a little dab of excess grease and smeared it on the underside of the newly cleaned gear.

Finally, I put the actuator back together and made sure it worked as expected (it did) before re-installing the rest of the parts.

---> Fixed in about 2 hours for free.