DIY: Replace Servo Sub-Assy

[MENACE]

Great post! Thanks for the step by step! I was having an issue with my temp servo only blowing cold or hot air. It would from one spectrum to the other. There was no way of adjusting the temperature.

I took my dash apart and unplugged the old one and plugged in the new one to test, and noticed the new one was doing the same thing? I watched the white center piece that moves the arm move once when I went from low to one step above? When i tried moving the temp higher, it wouldn't move even when I got all the way up to the highest temp. Any ideas on what else to check?

 

[utmba95]

Great post! Thanks for the step by step! I was having an issue with my temp servo only blowing cold or hot air. It would from one spectrum to the other. There was no way of adjusting the temperature.

I took my dash apart and unplugged the old one and plugged in the new one to test, and noticed the new one was doing the same thing? I watched the white center piece that moves the arm move once when I went from low to one step above? When i tried moving the temp higher, it wouldn't move even when I got all the way up to the highest temp. Any ideas on what else to check?

My guess is that the cabin temp sensor is not working right. It seems like it thinks the cabin needs heating at any setting other than LO.

 

[AuSeeker]

Great post! Thanks for the step by step! I was having an issue with my temp servo only blowing cold or hot air. It would from one spectrum to the other. There was no way of adjusting the temperature.

I took my dash apart and unplugged the old one and plugged in the new one to test, and noticed the new one was doing the same thing? I watched the white center piece that moves the arm move once when I went from low to one step above? When i tried moving the temp higher, it wouldn't move even when I got all the way up to the highest temp. Any ideas on what else to check?

My guess is that the cabin temp sensor is not working right. It seems like it thinks the cabin needs heating at any setting other than LO.

The temp sensor is my thought as well, I would check it for a good connection and make sure it's not clogged/dirty with dust, it's located just under the ignition switch behind the little slots on the trim panel.

 

[MENACE]

Thanks all! I'll check it this weekend and will let you know if that solved the issue!

 

[46runner]

This is really awesome and well documented. So how long should this really take us if we do on our own with all the correct tools you mentioned and new screws? I just called our local Toyota dealer and with me having part they want $700 do do this repair? Said something about removing dash and taking out box, etc. almost all the way to firewall? Why would Toyota be taking out the box as I told them it's just the upper motor on the left side of glove box. Sounds kind of fishy to me after listening to them, but I am concerned about the patient part where you mentioned about the motor and position of gear being put back on.

It took me about 4-5 hours. Maybe it would have been quicker if I removed the dash? Dunno. It's doable if you are handy and have the patience. The risk of level is low, meaning the car will still be drivable; so if you can't get it back together you can always take it to a shop to bail yourself out.

 

[46runner]

1. Thank you for the incredible detail and step-step walk through. This is immaculately done and I greatly appreciate it!

2. Do you recommend changing both servos for the convenience factor while having all that open and out? I took apart my glove box today and can feel the bottom servo buzzing/vibrating, but my temp can still be adjusted. The mode setting (top servo) is not changing. Just go ahead and change both, or knock the top one out?

3. Through this forum and talking to others, some recommend drilling a hole through air filter port to easily access the mount screws. Looking back, do you recommend this as opposed to going the route you took?


Thanks again for the amazing post.

The servos are a wear part so they will fail eventually. Knowing that, I'd replace both at the same time.


I didn't think to drill a hole, but it sounds like it would make accessing the screw a lot easier.

 

[08TxRunner]

The servos are a wear part so they will fail eventually. Knowing that, I'd replace both at the same time.


I didn't think to drill a hole, but it sounds like it would make accessing the screw a lot easier.

Yes, trust me - drilling the hole is the key. I bet I could do both servos at this point in an hour because all the time spent on the project is getting at those two bastard screws. All the other screws are fairly easy.

 

[utmba95]

Yes, trust me - drilling the hole is the key. I bet I could do both servos at this point in an hour because all the time spent on the project is getting at those two bastard screws. All the other screws are fairly easy.

I also used a $10 ebay boroscope/camera connected to my phone to help get the screw in the right place along with magnetizing the screwdriver.

 

[UURunner]

I've changed out pretty much all of my servos, and one is going out again. I can't remember which of the two to the left of the glove box I was changing out, but there was one screw that was impossible to get to. Rather than remove a bunch of stuff, I drilled a hole through the slot where the cabin air filter sits so I could get a screwdriver on the screw. I then used a $10 ebay borescope connected to my cell phone to watch for when the screwdriver was seated. I taped the screw to the screwdriver for the reinstall.

Holy crap, you drilled a hole? Wish you took a picture!

 

[MENACE]

You were right! It was unplugged and the hose was disconnected. Must of happened when I got my alarm installed... SMH. Thank's all for the info!

My guess is that the cabin temp sensor is not working right. It seems like it thinks the cabin needs heating at any setting other than LO.

 

[joesergi1]

Great Post

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

 

[46runner]

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!

 

[Jacob416]

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

 

[stump_jumper]

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!

 

[08TxRunner]

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.

 

[ThatT4RGuy]

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!

 

[That_Titanium_4RNR]

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!

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

 

[08TxRunner]

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.

 

[That_Titanium_4RNR]

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.

 

[08TxRunner]

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