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Are there photos showing how to take off the U-shape plastic cover in order to open the area to access and see the Mode Servo?
My wife's 2000 RX300 has the U-shape cover with vertical dividing lines on the driver and passenger side walls. There are plastic screws near the firewall. I am not sure how to start taking off the cover. Do I need to unscrew the 2 plastic screws or simply snap off (somehow by brute-force) at the dividing lines?
The mode servo and the air mix servo are on the passenger side at the corresponding area you show in the photos. For the cover screws, you unscrew them just a half turn or so and the center pops out so you can remove it. You can also just reach your hand behind the cover and push it out.
Last weekend I took off this Servo model and opened it. I don't see anything damaged. Everything appears in good physical shapes. So I cleaned the short-arm sprint contact points and put the pieces back together. This worked for 2 days without the rapid-clicking noise. Although periodic but the rapid-clicking noise came back on the third day.
This weekend I took off the Servo again. As the photos show, everything appears normal and nothing appeared out of position. The notch on the drive axle (photos #3 and #4) is solid strong and the motor axle has very little movement in the axle dimension because the end cap keeps it tight (photo #5).
There seems very little I can do I cleaned the sprint contact points and bend them back just a little. The contact circular plate (photo #6) appears being used just about 1/4 of the pie and there are signs of wore tracks (photo #7 after cleaning). The circular plate appears to serve as adjustable resistors and the wore out track signs could change the resistor values. There is nothing I can do but cleaning the plate and put thin coat of die-electric grease on the plate and on the sprint contact points (photos #8 and #9). Then I put all pieces back together. In the whole process, I managed to break a locking tab (photo #10). As there are mounting screws on both side of the tab, this broken tab would have little effect after the Servo unit is mounted to its position.
As the vehicle has been placed on the drive way for 6 hours under the sun at 90F (in my prior experience the rapid-clicking noise typically appear when the weather is above 70F/75F) , I started the engine and circulated through the many positions of the air condition system and the rapid-clicking noise is not present. Considering my last week's experience, I pray for a lasting effective repair.
I personally went through servicing/visual_check of servo motor and then once lubing the external arm. The cure was replacing the servo.
The rapid fire/noise which happens for about 5-7 seconds and then gets abandoned was happening for my theory is that motor is commanded to go into say "all air through top vents" and due to lack of power or not able to overcome the resistance of the external arm motion (opening ducts) does not advance .. the contacts tell the controller keep energizing the advance and after many attempts the circuit quits.
You try aiding the arm by nudging it and the noise will quit.
If you have kept the air flow in Auto, the poor thing has been overworked.
Thank you for sharing the insight. My second try did not last long and the rapid clicking noise came back this morning when the car started for the first time of the second day. So I have got a job for the coming weekend.
For reinstall the servo, is there a reference table about the servo arm position with the mode shown in the display? Reading through the posts on this thread, Dr. Dan mentioned that when the servo arm is in the highest position, it corresponds to the display setting of "all in your face" mode. I guess it is important as a new replacement servo may come in with it's arm in any position and I better match it with the right mode select on the display when reinstall the replacement.
Thank you for sharing the insight. My second try did not last long and the rapid clicking noise came back this morning when the car started for the first time of the second day. So I have got a job for the coming weekend.
For reinstall the servo, is there a reference table about the servo arm position with the mode shown in the display? Reading through the posts on this thread, Dr. Dan mentioned that when the servo arm is in the highest position, it corresponds to the display setting of "all in your face" mode. I guess it is important as a new replacement servo may come in with it's arm in any position and I better match it with the right mode select on the display when reinstall the replacement.
I simply moved the part on the RX to match the position of the arm on the servo.
On my 2003 RX300, I've had intermittent clicking for a while. This week, I started hearing a loud humming from behind the glove box. Video below. Is this a servo? Any ideas are appreciated.
On my 2003 RX300, I've had intermittent clicking for a while. This week, I started hearing a loud humming from behind the glove box. Video below. Is this a servo? Any ideas are appreciated.
Yes it is the air mode servo. I had the same loud noise. I took the servo out, open the housing, took the motor out. There is a metal piece press fitted on the motor shaft. Pried that piece a little away from the motor such that the worm gear has very little play when everything is assembled back in the housing. No more annoying noise. No parts purchase is necessary.
I have replaced the Mode Servo unit with a genuine Toyota part for a month now. As I reported some 2 months ago, the rapid-firing clicking noise came early this year - it used to be only during the very hot summer. I took off the Mode Servo unit a couple of times and cleaned the parts, but the same rapid-firing noise always come back the day after the cleaning. So, a replacement part was ordered.
The new Mode Servo was then installed. In the month afterwards, the same rapid-firing clicking noise came back several times. In most cases, if I turn the key to the ON position and do not hear the clicking noise, it is likely that I will not hear the noise back during the run. If the clicking noise is present when the key is in he ON position, in most cases I just turn the key back all the way, wait for several seconds, and turn the key to the ON position again and the noise may not be present. Sometimes if the clicking noise is present when the key is in the ON position, press the MODE button to shift the selection may stop the clicking noise. Sometimes, pull out the key entirely may also stop the clicking noise from happening in the next ride. If the rapid-firing clicking noise comes back during a ride and changing the MODE selection doesn't help to stop it, exercising the above while at a RED traffic light may do the stopping trick.
In my case, replacing the old Mode Servo unit with a new unit does appear to reduce the frequency of occurrence to a tolerable level, even though I hoped to get rid of the noise once for all.
The rapid clicking noise [different from the constant chatter] is because the servo is unable to push the dampers ... weak motor or things biding that the new motor can not overcome it.
05-10-17, 11:33 AM
