Thanks so much for this great post. I had the 10 second clicking / humming noise as well and decided to follow your well described instructions. For my issue I knew that the air blend servo was the issue because I could touch the servo and feel the humming. The air directional servo for defog, floor, dash vent, etc. was working properly.

To be honest, I got lucky because did some of the disassembly to get to the lower servo and the disconnected the wiring. I plugged the servo back in and the humming noise went away and the servo seems to work fine now. I am not sure if it needed to be reset or what actually happened, but I have heat now and am able to control cabin temperature. This issue happened 6 months ago and the dealer fixed it quickly without charging me anything after having a routine service. They said the air blend door was stuck shut and if it happened again I would need to remove the dash and would be costly.

So, I ordered the part and wanted to try to fix the problem myself. This was my experience and just wanted to share. I have 245,000 miles on my 2004 SR5 and didn’t want to pay for a big repair I could potentially fix. Stuck with the part, but maybe I do need to replace it in the future.

Peace,
Joe

Similar. My original servo was also fixed after I jiggered it. It lasted for about a year before it failed again. Maybe it's just a sign of it's about to fail. But I hope yours holds!

I disassembled the mode servo and cleaned the contacts and that seemed to work for now.

Thanks for your post. Replaced the fan mode servo yesterday in a few hours. The endoscope was a great help as was drilling the hole. One think I missed for a few minutes is make you hit the recirculate button to give you a little room to work. Thanks again for your detailed instructions!

Yes! Open that lid for a ton of extra room. Glad it worked out for you.

I've been hearing buzzing and clicking noises behind my dash for the past 8 months. So far everything still works, but i'm glad I came across this thread. Will help a lot when the time comes. Great write up! Thank you!

Wish I had read your post before starting...I tried pushing it up by hand a broke it. Not sure what to do now

You probably broke the recirc servo on the right side of the fan box.

To be honest, I was super frustrated and didn't really closely inspect what broke, but I am pretty sure that the "bellows" thing itself broke. Now after reading it seems that i may have broken where it attaches to the hvac box. It almost looked like a plastic pin type thing that it pivots on and that is the area where the plastic shattered. Not sure how I would even go about replacing that or finding a new one. Can't find a part # anywhere.

Honestly, I would tape it shut and not worry about it. Unless you need outside air for some reason.

Alright so myself and @papabeach followed this thread yesterday and installed my new servos. Here are some thoughts/recommendations:

-Bought both pieces off ebay for a total of $236 shipped
-Test the two new ones before you go through the hassle of removing the old ones and installing the new ones
-Drilling a hole makes accessing the one screw 1000x easier
-The angle is awkward, so we had to drill in 3" on the side of the air filter cabin to access the screw
-Do NOT strip that screw, it will make your life miserable
-When you put the lower servo in first, make sure you go ahead and put the screw in the slot and line that one up first, it will make remounting the assembly much easier

Results:
-Hot and cold air are fine
-Defrost is fine
-No buzzing or obnoxious noise
-When selecting the option to blow air to your feet, it still blows out of the head option
- @papabeach is a genius
-Thank you to the original thread owner for the details

Hope this helps!

The original post and this thread are awesome and were key to success with this repair. I signed up to the forum just so I could add my two cents regarding replacement of the "air mix servo". I was a little confused by the descriptions of drilling into the side of the air box. Since I did my repair, but prior to this post, someone else posted pictures of the air box. A picture really is worth a thousand words!

I would just add that the 8 Pc Right Angle Screwdriver Set by Pittsburgh from Harbor Freight made removing and replacing the bottom two screws fairly easy. I also purchased a 90 degree angle drill attachment from Harbor Freight (about $30, item #69337 3/8" Angle Drill Attachment with Keyless Chuck) to help with the drilling.

Two tips: 1) Unclip the wiring from the blower fan and unscrew the three bolts holding the fan in place to access from below. 2) Set the air inflow on the dash to recirculate to slide the accordion door open vertically to see what you're doing.

I drilled further back in the box to provide a straight shot to that top screw which is not visible. I used about a 10" long Phillips screwdriver (#2 I think) and, once it felt seated in the screw, applied pressure to keep it from stripping the screw. As suggested by someone else, I did not replace that top screw. If I need to replace it later, I'll have to either find a long magnetic tip screwdriver or maybe use some light glue to hold the screw to the screwdriver while I get the screw positioned. Covered the hole in the air box with duct tape on both sides.

Hope this helps the next person!

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Good thread on fixing the servo motors on the passenger side. My problem is the servo motor on the driver side, down near the gas pedal. I can see it trying to work the arm when the AC is on but not really moving the door. It will try and try while I'm driving and the sound from the servo is noticeable even with music on. Going to take a look at it this weekend and see if it's really the motor or if the blend door there is broken and the servo just can't move it.

$131 for a new servo from McGeorge Toyota - Servo - Toyota (87106-35170) | Toyota Parts

Did you wind up replacing the driver’s side servo? I have a noise coming from the driver’s side but so far, I’ve only been able to find writeups on the passenger side.

No, I've left it alone. It makes noise every now and then but it still works fine. Too much hassle to pull it out and fix/replace it.