DIY: Replace Servo Sub-Assy

[46runner]

Symptoms:​

1.Ten seconds of fast clicking noise (so fast it sounds like buzzing) from the dash area upon starting the car​

2.Fan only blows through front vent. No air being blown to windshield or to feet vents​

3.Fan temperature doesn’t change


I decided to replace:

SERVO SUB-ASSY, DAMPER (FOR MODE) 87106-35120​

Controls where the air flows from (vents, defrost, etc).​

Under the glovebox, mounted on the center console, top position​

SERVO SUB-ASSY, DAMPER (FOR AIRMIX) 87106-35180​

Controls the fan temperature​

Under the glovebox, mounted on the center console, bottom position




Update: Post #12 offers a tip about accessing some of the screws for easier removal of servo. Posts #41 and 42 have pictures for drilling a hole to access the difficult screw.












continued in next post...
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[46runner]

DIY continued

continued...

 

[4RunnerMexico]

This is fantastic.
Thank you!

 

[2003-4x4runner]

Awesome, thank you for posting!

 

[RedRumt4r]

just saw it i will try dis thanks!

 

[druidspath]

thank you

I need to do this, was just unsure of HOW to get the servo OUT of the vehicle. Now if I can just find them at a good price

Maybe I can find one at a salvage yard... surely its the same part in any common Gen 4Runner... but what about an FJ? or another Toyota vesicle....

 

[druidspath]

Not clicking, buzzing

Hello all,

I see alot of comments about a 10 second clicking noise when starting their t4r, but mine makes a buzzing sound, not a clicking. could this also be the servo? That thing is a bugger to try to get to. Found one at a salvage yard, but despite the salvage vehicle being throughly stripped down, i still could not see how to access the back top screw to remove the servo, much less in my personal 4runner. I need to examine/study the above posts closer, but dont want to go through the trouble if it is NOT the servo.

anyone having a similar issue? Please comment or PM. This is driving me nuts

 

[AuSeeker]

Hello all,

I see alot of comments about a 10 second clicking noise when starting their t4r, but mine makes a buzzing sound, not a clicking. could this also be the servo? That thing is a bugger to try to get to. Found one at a salvage yard, but despite the salvage vehicle being throughly stripped down, i still could not see how to access the back top screw to remove the servo, much less in my personal 4runner. I need to examine/study the above posts closer, but dont want to go through the trouble if it is NOT the servo.

anyone having a similar issue? Please comment or PM. This is driving me nuts

Where is the buzzing sound coming from(?), if from behind the glovebox, I'm not sure what it is, but if it sounds like it coming from behind the instrument cluster it's most likely the pump on the brake master cylinder and is normal for it to run 10 or so seconds when you first turn on the ignition and then every second to third time you press the brake pedal, if it's seem to run more often than that then the pump could be going bad.

 

[4RunnerFJ]

Hello all,

I see alot of comments about a 10 second clicking noise when starting their t4r, but mine makes a buzzing sound, not a clicking. could this also be the servo? That thing is a bugger to try to get to. Found one at a salvage yard, but despite the salvage vehicle being throughly stripped down, i still could not see how to access the back top screw to remove the servo, much less in my personal 4runner. I need to examine/study the above posts closer, but dont want to go through the trouble if it is NOT the servo.

anyone having a similar issue? Please comment or PM. This is driving me nuts

It could be the servo. I had the same issue last year. That buzzing was annoying as hell. My problem was with the servo for mode (the one that changes which vents the air comes out). The servo is located to the left of the blower motor above another servo. Since it's easy to do, I recommend removing the glove box and the secret compartment to expose everything and then crank the 4R. This might help you diagnose the problem better. You can watch the servos work while putting them through their paces.

I used a T-handle screwdriver to access the screw in question. It took some patience but it can be done. Same thing with the install...patience.

 

[firefoxed]

I decided to replace:

SERVO SUB-ASSY, DAMPER (FOR MODE) 87106-35120​

Controls where the air flows from (vents, defrost, etc).​

Under the glovebox, mounted on the center console, top position​

​

SERVO SUB-ASSY, DAMPER (FOR AIRMIX) 87106-35180​

Controls the fan temperature​

Under the glovebox, mounted on the center console, bottom position​

Another to add to my to do list.

Excellent post and might be just what I need if I have read the posts on the forum correctly.

I have no heat coming to the passenger side and I believe this is normally the blend door. So is the blend door the same as your top servo? SERVO SUB-ASSY, DAMPER (FOR MODE) 87106-35120

There seems to be some different names being used to describe the blend door.​

 

[Ventil8]

I think I might have this issue as well. I sometimes hear a clicking sound coming from the vents. Then this week, when we were getting cold temps in the 30s and lots of rain in Central Texas, I was driving around and I didn't think I was getting enough air to the windshield, side vents, and foot vents. Consequently, the inside of the vehicle started fogging up really bad. The next day, the vent seemed to work because I turned the blower to the highest setting and I could feel the air blowing on the windshield and no fogging inside. I'll have to research this more. Thanks for the DIY tips and pics.

 

[utmba95]

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.

 

[46runner]

Hello all,

I see alot of comments about a 10 second clicking noise when starting their t4r, but mine makes a buzzing sound, not a clicking. could this also be the servo? That thing is a bugger to try to get to. Found one at a salvage yard, but despite the salvage vehicle being throughly stripped down, i still could not see how to access the back top screw to remove the servo, much less in my personal 4runner. I need to examine/study the above posts closer, but dont want to go through the trouble if it is NOT the servo.

anyone having a similar issue? Please comment or PM. This is driving me nuts

yeah, sounds like buzzing too

 

[BMeister]

I only have one symptom which is the clicking noise. Which one of these servos is the culprit?

 

[rgcary]

continued...
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View attachment 319767

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.

 

[truckhigh]

You did an awesome job!!!!

I know you went far and beyond with this thread. if you have a chance could you test the old servos and see if and how they failed. Or see if there was resistance in the box/arms/flaps that would cause these motors to fail. maybe you could prevent some from failing or keep failing. I think mine is starting to. Thanks man. i would if i had some to open up.

 

[utmba95]

My analysis 10 years ago was that the contact arms lost their spring. I could bend them a bit and they would work for another 6 months. Possibly putting a piece of foam behind them might help them make contact.

Grinding/clicking under dash - air mix servo - Toyota Nation Forum : Toyota Car and Truck Forums

 

[08TxRunner]

Just replaced both left hand side servos today - huge thanks to the OP for this thread. By FAR the best piece of advice was this:

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.

The bottom right screw for the upper servo, and the upper right screw for the bottom servo, are right next to each other and inaccessible. I think typically the vast majority of the time needed for this project is on these two screws. Drilling a hole in the side of the box on the left, just above the fan, gives perfect access to these two screws. Magnetizing the screwdriver with a magnet makes putting them back in a breeze. A little Gorilla tape sealed the hole I drilled. I completed this entire project in less than two hours. Works perfectly now - big thanks to everyone who contributed.

P.S. I saved the old servo brackets, so if anyone needs them PM me. I'll send them to you for a few bucks shipping.

 

[CookieRoe]

sUbscribed.

nice! thanks!

 

[SHagood]

yeah, sounds like buzzing too

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.