Heater blowing cold air
CL Community Team
Joined: Apr 2001
Posts: 16,503
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From: Austin, TX
Lexus Champion
Joined: Aug 2007
Posts: 4,507
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From: Bethlehem Twsp. Pennsylvania
Driver School Candidate
Joined: Oct 2008
Posts: 2
Likes: 1
From: Texas
DIY AirMix Servo with Picture!!
It is not that hard of a job, but patience is needed. You will need to remove the glove box, two crews on top corners and two 10mm bolts on the bottom corners. It also helps to remove the small trim piece next to the passengers left foot. There is a plastic screw on that.
I was able to fix the servos (both were inop) by taking them apart, cleaning contacts, grease, etc. I do not know how long that will last. I have priced the servos at irontoad.com for $125.61 each. There is an airmix servo and a recirculation servo, the recirc servo controls the damper for vent selection. It sounds like you only need the airmix servo.
The servo is held in place by 4 small screws and the airmix servo is more of a pain to get off than the recirc. You will need to twist your body and use a lot of patience to get to the screws and remove. If your RX has been running let it cool down, less than an inch away from the servo are the lines to the heater core, that may be why this servo fails to much! It gets hot there!
There is a wired plug that you will have to press the tab and pull out. When installing make sure you match up the servo arm position to the door airmix door position. What I did is: turned the ign switch to "on" and set the controls to full hot and let the servo move the arm. then placed it onto the airmix door arm.
I was able to fix the servos (both were inop) by taking them apart, cleaning contacts, grease, etc. I do not know how long that will last. I have priced the servos at irontoad.com for $125.61 each. There is an airmix servo and a recirculation servo, the recirc servo controls the damper for vent selection. It sounds like you only need the airmix servo.
The servo is held in place by 4 small screws and the airmix servo is more of a pain to get off than the recirc. You will need to twist your body and use a lot of patience to get to the screws and remove. If your RX has been running let it cool down, less than an inch away from the servo are the lines to the heater core, that may be why this servo fails to much! It gets hot there!
There is a wired plug that you will have to press the tab and pull out. When installing make sure you match up the servo arm position to the door airmix door position. What I did is: turned the ign switch to "on" and set the controls to full hot and let the servo move the arm. then placed it onto the airmix door arm.
The picture shows the Air Control Servo and the Air duct that needs to be removed for access to the AirMix Servo (only the "painful" screw is shown on the AirMix Servo just below the Control servo and behind the duct). The two silver heater tubes (also shown) should be hot once the engine warms up.PS -- First time "poster"; hopefully the picture helps tell the story.
Last edited by TxAg85; Oct 23, 2008 at 11:41 PM. Reason: Label picture in text for clarity
Pole Position
Joined: Oct 2008
Posts: 334
Likes: 0
From: NC
Sweet! Glad it worked out for you. Nice picture, I wish I did the same thing! I don't know how long my servo repair job will last but when they go at least I know how to do it myself what that times comes.
This appears to be more common, I think the airmix servo is subject to temp extremes due to the heater core lines so close.
This appears to be more common, I think the airmix servo is subject to temp extremes due to the heater core lines so close.
Driver School Candidate
Joined: May 2007
Posts: 1
Likes: 0
From: fl
fix to heat problem
I have the same problem as the beginning post, cold air come out and the two pipes are hot, like someone said above there are 3 servos, and the servo that opens and closes the gate is broken, so i manually moved the gate and now i got hot air, i just have to buy a new servo. it is right behind the steel pipes. i got to it by taking off the glove box, and the panel on the center console on the passenger side on the left of where your feet rest close to the firewall, (i know its a bad explanation but if you need pictures i could post some.) anyway i noticed the servo is busted, so i just moved the lever by hand. (there are two servos close to each other, the one for the vents which is easy to see and the one of the gate which is closer to the firewall.
as i said if you need pictures i can post some.
as i said if you need pictures i can post some.
Driver
Joined: Mar 2002
Posts: 1,800
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From: Maryland
Driver School Candidate
Joined: Jan 2009
Posts: 5
Likes: 1
From: MA
So there’s someone else out there with funny temperature issues. I have written in the past regarding the NO HEAT to the drivers side only which is still an issue as winter is upon us here in Conn.
1. If you remove the glove box you can visually see the servos and adjust ***** to see them in action. You can see the servo move the vent door for the heat and adjust the defrost/dash vent/floor board direction diverter.
2. Note the vent behind the glove for the inside/outside air input which is servo 3 of 3.
3. In my 99 model there is a temp sensor just infron of my right knee when driving the vehicle. If you remove the lower panel, you can remove the unit and notice the fan speed change as mine did which I assumed meant it was working.
To this day I have no heat crossing over from the heater box to the driver side which is a pain in the butt. So, I had to be creative a provided a flex hose from the passenger side foot vent and crossed it under the air box over to the driver side foot area. Now my feetsies don't freeze in the way to work.
I suspect that there is a vent door fault inside the air box and I have no plans to remove the entire dashboard in order to investigate or pay the crazy price to replace. I have a 99RX with 180K mile and runs like a champ. Yes the tranny was replaced at 125K.
1. If you remove the glove box you can visually see the servos and adjust ***** to see them in action. You can see the servo move the vent door for the heat and adjust the defrost/dash vent/floor board direction diverter.
2. Note the vent behind the glove for the inside/outside air input which is servo 3 of 3.
3. In my 99 model there is a temp sensor just infron of my right knee when driving the vehicle. If you remove the lower panel, you can remove the unit and notice the fan speed change as mine did which I assumed meant it was working.
To this day I have no heat crossing over from the heater box to the driver side which is a pain in the butt. So, I had to be creative a provided a flex hose from the passenger side foot vent and crossed it under the air box over to the driver side foot area. Now my feetsies don't freeze in the way to work.
I suspect that there is a vent door fault inside the air box and I have no plans to remove the entire dashboard in order to investigate or pay the crazy price to replace. I have a 99RX with 180K mile and runs like a champ. Yes the tranny was replaced at 125K.
2000 RX300; 220,000 miles; Massachusetts
Last edited by jk00.rx300; Jan 12, 2009 at 03:38 PM. Reason: added year and mileage
Driver School Candidate
Joined: Oct 2009
Posts: 1
Likes: 0
From: SC
Thanks to everyone for posting - (especially TxAg85 for the extremely helpful photo). Last night I was able to repair my air mix servo, and have heat again. On the inside of my unit, I noticed the brush like contacts had worn through a spot on the electrical contact face of the gear, probably where it sat in a resting postion with the door closed. After cleaning, and rotating that larger gear so that the brushes now rest on a fresh spot, may have been what got it moving again. I don't know how long the repair will last, but at least I know I can eventually replace the thing later if I need to. My local dealer wanted around 180.00 for the air mix servo, and 250.00 labor. I had no bad teeth on any of the gears inside, but there is also a little worm gear inside, that turns the works, and it had rough edges, making it possible for it to get stuck against the inside of the case as it traveled along the moter drive shaft. Really thrilled to have saved 400+ 
.
.
Instructor
Joined: Oct 2005
Posts: 1,087
Likes: 129
From: pa
The Air Mix servo is on the bottom of the two servo boxes together. I played with this the other day, because both of my air servos are crap, even after I cleaned them up. The top controls the vents. I did order both from www.parts.com, they both run at about $117 each. I see it as if I buy them new now I will never have to do this and look at this again.
Also, I couldn't find the air mix servo in their drop-down menu. What category is it in?
Thanks.
Its under Air Conditioner and Heater......then....Evaporator and Heater Components.....
then.....Servo.... All three types are listed there. And yes these are all authentic toyota/Lexus parts. After I received my packing list the address of a Lexus dealership in Tampa Bay, FL. is where the parts come from. I called and spoke to them many times to get part #'s and they are very helpful. good luck!!
then.....Servo.... All three types are listed there. And yes these are all authentic toyota/Lexus parts. After I received my packing list the address of a Lexus dealership in Tampa Bay, FL. is where the parts come from. I called and spoke to them many times to get part #'s and they are very helpful. good luck!!
Driver School Candidate
Joined: Feb 2010
Posts: 1
Likes: 0
From: CA
ServoMotor axle broke
I have the same problem and I found out the head of the servomotor
connected with the level was broken. The head is actully part of a plastic
gear inside and it could not withhold the torge and twisted itself off.
I custom made a wood, files it to the right shape and glue it back. I tested
it while turning the temperature dial - everything worked well. After I mounted
it back, I saw the motor wouldn't not stop at low temperature setting and
the broke the wood center piece right there! Surprisingly, the torge is so
strong and the motor sensing circuit didn't work to stop it.
Would you care to comment what caused it? Is there something else, for
example temperature sensor, or control switch, etc caused the motor
running non stop?
Thank you,
JP
connected with the level was broken. The head is actully part of a plastic
gear inside and it could not withhold the torge and twisted itself off.
I custom made a wood, files it to the right shape and glue it back. I tested
it while turning the temperature dial - everything worked well. After I mounted
it back, I saw the motor wouldn't not stop at low temperature setting and
the broke the wood center piece right there! Surprisingly, the torge is so
strong and the motor sensing circuit didn't work to stop it.
Would you care to comment what caused it? Is there something else, for
example temperature sensor, or control switch, etc caused the motor
running non stop?
Thank you,
JP