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There is a rash of air mix servo motor failures in the 2001-2009 model Toyotas. In the last year, I've had bad ones on my 2003 4Runner, my wife's 2004 4Runner and yesterday my Dad's 2002 Avalon. Hopefully I can save you some time troubleshooting your vehicle and possibly allow you to fix it for free. I had my truck serviced under an extended warranty, and it took two service calls and over $2000 of warranty work. On the other two vehicles, I fixed the problem for free in about an hour.

Symptoms - Grinding or clicking noise coming from under the dash.

Diagnosing - You can usually look up under the dash towards the center of the vehicle and see the white plastic lever moving rapidly back and forth. The purpose of the servo is to mix cool air from the A/C or outside with warm air from the heater to match the temperature you have set. The white lever has a travel of 90 degrees. One extreme is all cold air (no hot air mix), and the other extreme is all hot air. The A/C computer sets the position of the servo based on the air temps and the desired temp setting. For the servo to make the noise, it has to be in the middle region between the two extremes. This is generally when the set temp is close to the actual temp. You can try moving your set temp from very cold to very hot and watch the white lever move from one extreme to the other. Note that if it's too hot or too cold, you might not be able to get the servo to stay in between the two extremes. When the lever is in between the two extremes of travel, it should be very stable although it may move a bit every minute or two. The broken ones continually move back and forth which makes the grinding or clicking noise.

Replace - If you see these symptoms, there is a small chance that something else is damaged, but it's almost certain that your servo is bad. Note that dual temp A/C's have servos on drivers and passenger sides. The easy option is to buy a new servo for about $100-$130. However, I have successfully fixed two of them using a screwdriver and pair of small, long nosed, needle nose pliers.



Repair - Unscrew the servo unit from the car and disconnect the electrical cable. Gently pry the plastic clips with a flat screwdriver so you can separate the two halves of the case. Take note of the orientation of the motor and the white lever so you can replace them correctly. (With a marker, put a mark on the motor and the large gear so it's easy to identify their positions). Snap the motor out. Under the large plastic gear (which doesn't come out) you will see about 6 copper fingers that rub on the back of the gear. I believe the problem is that the fingers lose their spring and do not press hard enough against the resistive coating on the back of the gear. Take a small pair of long nose, needle nose pliers and grip all of the fingers near the base. Bend the fingers slightly upwards. Check that the white lever is in the same position as it was when you took the motor out. Reinstall the motor in the correct orientation making sure its electrical contacts fit between the copper fingers in the case. You can now put the cover back on. Note that if you break a clip, it's probably not a big deal since the mounting screws will hold the unit together.

Testing - NOTE- watch your fingers! Without installing the unit on the car, plug the electrical cable into the servo. Run your AC or heater as above to move the lever from one extreme to the other and back into the middle region. If it no longer rapidly jumps around, it's probably fixed.
 

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Thanks utmba95. That's definitely what is making the grinding, cruching, ticking, clicking noise in my Camry. This problem obviously applies to many various Toyota vehicles, if not all of them. I know it applies to my Gen 5 2004 Camry XLE, which has the digital A/C & Heat control.

I sure wish that bugger wasn't so hard to get to underneath the dash of my Camry. I'm guesing it might be a little easier to get to in a 4Runner or trucks versus cars. You nailed the time when it makes the noise perfectly! I've been listening to the clicking noise for years whenever the outside temperature and inside temperature are about the same. There is no noise if the outside temperature is nowhere near what you have the A/C-Heat control calling for.
 

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I've had this problem for a few years, but I didn't see any problems with it, just that it was an annoyance. After seeing this thread, I had to try and do something about it.

If you not exactly sure what the problem is, here is a video I took about 8 months ago before I knew what it was and where exactly it was coming from


OP nails most of what you need to do. One thing that he leaves out is that it was quite difficult to remove the upper right screw of the servo housing to get it out. There is only about 2 inches width between the screw and some larger part of the A/C heating system [I think?]. The only way I could unscrew it was to hold a bit in there with my index finger on the middle part on back of it and my thumb on the end. In the other hand take a pair of needle nosers and start screwing downward, readjusting after each turn. This will test your patience. It only took a few minutes but felt like 20.

Here's a couple of pics throughout the process:

Take out the glove box and a few other parts for greater access.


The culprit:




Front of the unit:


Back of the unit: As OP said, take a pencil and mark the position of the arm. illustrated here by MS paint:


Housing open:


What you need to adjust. Just bend them downwards with needle nosers, try to make when all level.



Put it back together and insert back into vehicle:


Success! Hopefully I don't have to keep doing this, or buy another motor.

Thanks, OP. Must appreciated.
 

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I'm sorry if I seem a bit dense, but I have a 2003 4Runner that is having this problem. Basically, I have the grinding noise, and my 4Runner is stuck with the air conditioning on, which I only realized recently when we got cold weather. I was able to verify that it is the air mix servo that is messed up (the sound went away when I unplugged it) but I'm having trouble figuring out how to get that thing out.

Does anyone know where I can get a guide to taking enough of the dashboard off on the passenger side to be able to get this servo out? In looking at the photos posted by gillilanded they look nothing like what my 4Runner has in terms of the dashboard and trim, although underneath it's somewhat similar. The biggest problem is that I can remove the glove compartment just like I would for changing the AC filter, and I can remove the trim around it, but it's still blocked to where I wouldn't be able to get to it. I can post pictures if they would help but I figure if there's a guide out there that I can't find here or on Google that would save some time.

Thanks in advance.
 

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03 Highllander Limited, 3.0, with oauto temp control. Have had clicking noise for about a year. Dealer had no clue. Read this thread and removed the servo. Cleaned and bent contacts. Resistive material was worn thru in one spot. Now noise is gone, but I have no heat. Is it possible that the servo can cause no heat, or did I accidentally disconnect something while I was in there? Got a good source for a replacement servo?
 

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03 Highllander Limited, 3.0, with oauto temp control. Have had clicking noise for about a year. Dealer had no clue. Read this thread and removed the servo. Cleaned and bent contacts. Resistive material was worn thru in one spot. Now noise is gone, but I have no heat. Is it possible that the servo can cause no heat, or did I accidentally disconnect something while I was in there? Got a good source for a replacement servo?
As the OP stated, one extreme position of the servo is full cold and the other is full hot.
You may have re-installed it incorrectly or damaged it during your repair.
The first thing would be to observe it's operation when you move your control from max cold to max hot. It may not move immediately or quickly, so give it some time while your watching.
 

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To answer my own question, yes the servo controls both heat and cool. The 03 Highlander has 3 servos and are not interchangeable, One is the the driver's side of the center console, one to the right of the console (the problem) and one on the fan box. Mine was Toyota part # 87106-07081. The part # is not on the servo. Mine looks just like the one pictured above. I ordered one from Toyota Parts Barn for $134 and found I had ordered the wrong one. Got one from dealer to make sure I had the right one for $164. On the Highlander, you have to remove the glove box. Take the GB dampener loose (like you do to change the filter). Push out the 2 plastic pivot pins and remove the GB. Remove the white plastic air duct by removing one screw on the bottom and a plastic tab on the top. Remove 3 screws that hold the servo with a stubby phillips screwdriver. Pull the servo down and remove the wire plug. Problem solved.
 

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Have chased this problem for over a year. UTMBA 95 has it right on. I could see the lever under the glove box move back and forth by changing the temperature setting knob. No need to remove anything to see this but you need to be a contorsionist to look under there. Fortunately in this case I was able to get rid of the "chatter" by just cycling this lever back and fourth a few dozen times by turning the temperature setting knob all the way in each direction. This may be the easy way to start!
 

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Fixed!!

Thanks so much to the members of the forum for the great write-up and pictures.

I've got a 2004 Sienna and it had been clicking for 2 years - this year it had quit clicking, and would only blow cold air.

After reading through this article - took the part off - tested it

Indeed - it shook like crazy and wouldn't move smoothly

Took the piece apart and bent the pieces as per the pics

And - now - no chatter, and the van blows warm air on demand!

Thanks again - great forum
 

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With dealer parts and labor prices (and so far as I can tell, this part is dealer-only), these posts probably saved me $350.00. All it takes is some effort and a minor adjustment on the part, and the fix above really works!
 

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Annoying grinding sound from under dash

Good Day All,

I have a 2003 Toyota Premio RHD i have the grinding problem as well. mine is coming from near the center console but on the drivers side.

My ac on distributes hot air and nothing more could this be thsource of the problem.

I have attached a link below with the sound im getting as soon as im able to make a video ill do so and post it.

http://picosong.com/Lffv/


Someone please help.
 

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air mode servo

I have a similar problem, hopefully someone here has some experience with. My 07 Rav4 will not change air flow modes. It is hung up on the dashboard vents. Will not blow out the windshield defroster vents or the floor vents. The buttons on the controller appear to be working fine, because it shows it on the digital display, although I have not actually taken it apart and verified the output is actually firing. There has got to be some kind of valves or air duct "doors" that redirect the airflow using a motor of some sort!! maybe it's jammed up? idk.. thanks to anyone who may be able to help!
 

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Good Day All,

I have a 2003 Toyota Premio RHD i have the grinding problem as well. mine is coming from near the center console but on the drivers side.

My ac on distributes hot air and nothing more could this be thsource of the problem.

I have attached a link below with the sound im getting as soon as im able to make a video ill do so and post it.

http://picosong.com/Lffv/


Someone please help.

can someone assist in this matter please?
 

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Great post!

I've got an '03 Tacoma. My problem with the noise went on so long it evolved into something else. One day out of the blue the noise stopped. Completely. At the same time I no longer had heat. Based on this thread I can only assume the servo isn't functioning at all and the blend door is stuck in the cold position. Sound right?

Also, what controls the cable for the coolant value under the hood... the one directing coolant through the heater core? Mine is not moving.
 

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hi found this thread by googling.my 2004 highlander started doing this, was wondering if it only happens when the ac /heat is on or did any have it happen while it was off also? mine is clicking when off or on. it did stop but seems to start again, trying to figure out if this is my problem with the clicking
 

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Crude cheap fix for blend door actuator problem.

Thank you UTMBA95. This is an excellent post with wide applicability. I didn't have the clicking noise but my 2002 Toyota Tacoma pickup only blew hot air. The design of my servo was a little different but after I bent the contacts I got cool air. Mine also had leads attached to the inside of the cover with contacts to the power terminals on the little electric motor. I bent those too. Mine had a metal arm instead of the plastic one. My servo was relatively easy to get to. It is directly above the gas pedal on this vehicle.

Sorry I posted incorrect information. The blend door actuator is on the passenger side. The servo above the gas pedal is the mode switching servo they are similar devices.

The blend door actuator/servo was not working. A new one at the dealer is $186. I took the servo apart direct soldered wires to the drive motor contacts, drilled holes in the case to pass the wires out of the servo and installed switches on the center console to manually power the servo motor one direction or the other. A lot of work but fixed the problem for a few bucks.
 

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Great troubleshoot guidelines. Followed the steps and resolved my code 21 and 41 errors codes on Air Conditioning Climate Controller on my 1999 4Runner, 6 Cylinder. For added measure, I cleaned/sprayed the contacts on the controller with QD Electronic Cleaner.
 

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Time Estimate for Replacing?

I have a 2004 Highlander with the servo on the passenger side making the clicking/grinding noise. I took it to my mechanic and they just cleaned and lubricated the outside because they estimated that it would take 3 hours to replace. From watching froggy's videos, it appears to be a PITA to get out, but doesn't look like it should take that long. Anybody have any idea if that time estimate is correct or if they don't know what they're doing and I should go somewhere else?

http://vid159.photobucket.com/albums/t138/sma425/Mobile Uploads/8620032E-526A-4291-B40F-A7588A9A6583.mp4
 
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