Stemmer

I posted about this a while back and with advice from the forum discussed it with my local Lexus and Toyota dealers and an indy. The Lexus dealer had no idea what I was talking about and blew it off. Toyota looked into it and told me they had to remove the entire dashboard and it would be about $1,200. The indy did not want to get involved with it. I let it go b/c no one would fix it reasonably and the symptoms abated a bit. Well, it's back fairly frequently. It's a loud ticking or clicking sound that seems to be coming from directly behind the center console. The heat and A/C work fine and the sound does not get effected by whether the heat or A/C is on or off.

A friend of mine is very handy for DIY and for a case of beer might help me out. My thought is to have him follow the below instructions from an earlier post and buy a replacement part. I figure if we are going to try and do this, might as well replace the part rather than clean it and later find the cleaning did not work.

Questions, 1. Anyone doubt this is an air mix servo issue? 2. Can someone post a link to the correct part to buy? 3. Are the below instructions correct, although I'm inclined to replace rather than clean. Thanks.

The noise is coming from the servo motor that moves the door for the "mode" button. This servo moves diverters to change from vent to floor, etc.
- I popped the bottom panel off under the glove box.
- I then removed the glove box assembly. 2 screws up high, 2 bolts down low.
- With the key on engine off you can press the mode button and watch the servo move. Turn the key completely off.
- Remove 3 screws and plug to take the assembly out.
- Do not attempt to rotate the arm on the end of the servo. It engages w/ a worm gear. Turn it and you will break gears.
- The servo is a snap together unit. Carefully take it apart w/ the arm side down.(so gears don't fall out)
- inside you will see multiple wiper fingers that make contact w/ a gear. Carefully clean these w/ alcohol and a cotton swab.
- Redistribute the contact grease on the wiper pad w/ a clean finger (any oil or lotions on skin will mix w/ the grease and make the copper contacts corrode.
- Carefully snap unit back together.
- Clean contacts on the outer part of servo also w/ alcohol.

salimshah

There are more than 1 servos to handle A/C behind the dash.

By your symptoms, I am leaning towards the MODE servo. [different from the mix servo]

I would suggest removing the glove compartment and and touch each servo to figure out which is trying to move and causing the problem.

Before popping the servo open, you need to see if the problem is in the links (the ones the servo tries to move). I had to lube the links and that cured the servo problem.

Each servo is about $150 ~180 (even 200 at the local dealership). People talk about cleaning the contacts are really trying to redistribute the grease.

Tip: Mark the position of the arm if you plan to open the servo. You want it assembled the same way,

Salim

JAB

For what its worth, I tried to open up my servo and clean it, as suggested above. I eventually got it open, but several clips broke in the process. I concluded that considering the amount of work involved in getting it out it was best to put in a new one. Haven't regretted it.

maxSteel

Its hard to believe the dealer is unaware of the mode and mix servos.

I replaced both. i forget which is which, but one of them is way too annoying to remove to hassle with trying to fix it.

Stemmer

I appreciate all the responses. Salim, I got the below response from another Lexus dealer, you are correct about the multiple servos. Putting this all together it would appear likely that it's one of the two motors located behind the console. Apparently there are two units in the dash area, and this dealer wants about $500 each or $1,000 to replace them both. So my understanding from what you and the dealer are telling me is there are two mode servo's behind the console and you suggest going through the glove compartment and replace the one that's trying to move. Of course it would have to be done when the clicking is occurring I presume to figure out the faulty part. This leaves me with two questions, are the two mode motors behind the console the same part for replacement purposes and is this the correct part?

http://www.lexuspartsnow.com/parts/l...106-30371.html

Thanks as well JAB and Max, I definitely agree with replace as opposed to repair. Dealer reply:

The vehicle has four servo’s in the dash…..three of which will fail (make noise or stop functioning) over time. The pricing for replacement of the servo’s is as follows: the units in the dash area would run $495.82 each, the servo located towards the rear of the heater core would run $729.82. The vehicle would have to be seen/diagnosed by a technician to figure out which servo is malfunctioning. We would be happy to schedule your vehicle for repairs

thomas1

How sad, the prices for replacement are rediculous. Should be a one hour job and even with $130/hr it should be only about $330...As I get older I am getting closer to those days that I wont be able to do it my self....Sucks.

salimshah

https://www.clublexus.com/forums/rx-...mix-servo.html

look at post 40.


Thomas1 ... I agree with you ... I need lot more light as compared to prior years. Hands are still stable to perform surgery ..

BUT

What you and I feel are no different from our parents/grand parents felt in their days. Life keeps going on, some how

Salim

maxSteel

Those dealer installed prices are insane. Of course, if the heater is still working fine you could ignore the noise for now. I changed mine when the mode no longer directed defogger air to the windshield.

At the time I ordered both the mode and the mix servo. But if I had taken the time to check I might have just ordered the mode servo. That was my issue to begin with, and that servo is the easy one to replace. Getting to the area is easy. The only reason the mix servo is hard to change is because 2 of the three screws are obstructed. It takes a lot of coaxing to get them out. But since I had already ordered the part I went ahead with it.

I'm confused by the dealer reply where he says there are 4 servos. I'm looking at the chart, and I only see three:

Air outlet servo - this is the 'mode' servo
Air inlet servo - I think this one is for recirculating cabin air instead of getting outside air
Air mix servo - determines the temperature

What is the 4th? Does your car have independent temperature settings for the driver and passenger side?

salimshah

My mode servo had been cycling with noise for a while and eventually was unable to move the arm. I procrastinated for a while and then my blower motor speed controller went out. It could have been a coincident, but the heat sink sits in the path of the air flow (duct work). The controller is not hermetically sealed, so I opted to buy a new one. When I replaced it , I lubed the levers of the mode arm and things are fine once again.

Who knows if the air flow would have been fine, the speed controller may have lived a bit longer.

Salim

Stemmer

I don't have independent temperature control, but the dealer response indicates only three motors could fail so this mysterious 4th one is probably something entirely different. I posted on this issue to begin with b/c I was driving someone and the RX began clicking fairly loudly and for a while and my passenger was asking about it. Naturally, like going to the dentist and your tooth stops hurting, since that time it's hardly doing it. I think I might let it go until and unless I have air flow issues since I have had it intermittently for a couple of years without issue, even with Salim's word of caution. I appreciate everyone's responses and believe I now have the needed information to address the issue if I decide to try a fix.

code58

I have dealt with this more than once and it has always been the air mix servo. Those that I have dealt with have always been because the tiny little brushes in the tiny little Chinese motors are completely worn out and even trying to tighten the brush holders up didn't help. When you get the stuff out of the way (only takes a few minutes) you can see the AMS. Start the car and operate the the aervo through the different positions and you can visually see why it makes the "gerbil" sound. The little motor is trying to get the "over-center spring" over center and it's not able to do it, but it keeps trying. It's easy to see.

Just realized I may be calling it the wrong thing. It may be the "mode" servo. Anyway, it's the one closest to the floor. There have been really good write-ups with good pictures on this very servo. One suggestion I would make. One of the Phillips screws is hard to get to because it's kind of behind the pipe. Use a #1 instead of a #2 Phillips screw driver and it'll be a lot easier to unscrew at an angle without slipping out.

thomas1

I agree, hate when folks are ripped off....is there no integrity out there.?

Trinimd1

Last month mine starting making a loud noise when I hit the mode button to head rather than foot.
It lasts about 20 seconds then goes away.
When mode for the head is selected
Air only comes out of the 2 side vents closest to the driver and passenger windows.
The center console above the radio has no air. The rear console has no air for backseat.

It seems to be stuck between head and foot.
Is it possible to move the level manually and leave it one position (head)?

salimshah

Gain access to the servo. Assist the servo arm that is stuck while operating the servo.

Remember to disengage Auto-mode as the servo will start cycling.

Salim

code58

What Salim says is true. The problem is the weak motor is unable to "get over the hump". There is an overcenter spring that is there to KEEP it in that position, once it goes over center. Unable to get over center it just "whines" that it's "fallen and can't get up". If you do as Salim said, access it and help the arm overcenter and then disable it in that mode, it will stay there.