oneround

Today I replaced the HVAC mode door servo box on my 2002 SC430.

Problem: Air only coming out from defrost vents.

The mode button and the climate panel display both appeared to be working (verified OK after the fix). That is press the mode button and the climate panel display would switch from face vents to floor vents, etc., but there was no change from flow only coming from defrost vents.

Running the AC (think warm, humid Florida) resulted in my windshield getting cold enough at the bottom that there was condensation on the outside of the windshield.

This was a 1 or 2 banana job, but it was a bit frustrating holding the new servo in place while getting screws started. Had to magnetize my screwdriver. Would have been handy to have 3 hands, but barely room for two in there.

I found a GS300 video that outlines in all essential aspects that which needs to be done on the SC. The Youtuber did a better job than I could have managed.

For those not interested in watching the video, here's the Cliff Notes version:
1) Remove plastic panel under glovebox, disconnecting the floor light and set aside.
2) Remove glovebox, disconnecting electrical connectors (3 or 4 I forget) and set aside.
3) Pull off a joined white wire connector set that's visibly in the way of getting rear screws out of the servo (connector is attached to flat metal bracket just to right of servo).
4) Remove mounting screws and remove servo.
5) Disconnect wiring connector from top of servo motor box.
6) To install, reverse (rearranging wire bundles as needed), taking care to get the two pins correctly interfaced between servo motor and rest of system.
Note: Describing the proper pins insertion is beyond me, watch the video if doing this and you're uncertain. Getting these pins in place, then getting a screw started enough to hold the servo in place so the pins don't lose position was the most frustrating part of the job - due to position and lack of room to work.

Only 2 differences with the video noted: 1) I didn't need/use a ratcheting screwdriver, and 2) the SC has a flat metal bracket where the GS had a tube that held a wire bundle that has to be disconnected to get screwdriver room for the screws nearest to the firewall. However, the wire bundle removal method was basically the same.