RX300 fan noise (blend door motor)
08-20-13, 08:49 PM
#16
Driver School Candidate
I have a '99 RX300 with 95k miles. Recently, I am hearing a constant noise coming from underneath the dash on the passenger side. The noise sounds like the fan switching modes/stirring. This noise occurs both when the air is on and off. Has anyone else had this problem? I took my car in the local dealership, and the service consultant suspected that it could be the blend door motor.
Anyone with any insight would be greatly appreciated. I made an appointment for Wednesday, July 18th, so I'm hoping someone can shed some light before I go in.
thanks!
--jason
Anyone with any insight would be greatly appreciated. I made an appointment for Wednesday, July 18th, so I'm hoping someone can shed some light before I go in.
thanks!
--jason
Last edited by abn503; 08-20-13 at 08:50 PM. Reason: grammer
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DeeBee3 (08-03-21)
08-22-13, 07:49 PM
#17
Driver School Candidate
Servo motor lubricant and contact fingers
it may be this(from another forum)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 whiper fingers that make contact w/ a gear. Carefully clean these w/ alcohol and a cotton swab.
- Redistribute the contact grease on the whiper 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/ alcohal.
The other option is to have Lexus diagnose this for you and hit you for $160 for the part plus ~ an hour or 2 labor.
So far the noise is gone and the HVAC system works properly. I will post any updates if the problem comes back. I think the problem was caused by crusty contacts in the servo that were creating a poor signal back to the computer that controls it. Now that it has a clean signal, all is well..... I hope!!!
- 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 whiper fingers that make contact w/ a gear. Carefully clean these w/ alcohol and a cotton swab.
- Redistribute the contact grease on the whiper 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/ alcohal.
The other option is to have Lexus diagnose this for you and hit you for $160 for the part plus ~ an hour or 2 labor.
So far the noise is gone and the HVAC system works properly. I will post any updates if the problem comes back. I think the problem was caused by crusty contacts in the servo that were creating a poor signal back to the computer that controls it. Now that it has a clean signal, all is well..... I hope!!!
03-18-14, 10:08 PM
#18
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Thanks Thomas1 and a few additional tips
I've had the same intermittent noise for a while so I was really grateful to find this thread. I printed out and followed Thomas1's steps and now the problem is completely fixed! To help others, I wanted to add these photos (too bad we can't just past a photo) and tips.
Make sure you have a 10mm socket screwdriver since the lower glove compartment screw is hard to reach. I had to use a screw driver to hold the socket.
After I opened the assembly and cleaned the contacts, I notices that the brass bushing with a flange on the motor shaft slid up and was not consistently engaging the worm gear. I pushed it down with a screw driver to secure it into the worm gear.
Finally, I didn't keep track of the cam position when I took the assembly off so I had to reopen it and check the proper orientation before putting it together. After the assembly was put back in place, the pins were not in their proper place so I had to snap the plastic cam over the pin. I am glad that I check the operation by pressing the vent controls.
It took me a little over an hour, but finding this rather simple and inexpensive fix was fantastic!
Make sure you have a 10mm socket screwdriver since the lower glove compartment screw is hard to reach. I had to use a screw driver to hold the socket.
After I opened the assembly and cleaned the contacts, I notices that the brass bushing with a flange on the motor shaft slid up and was not consistently engaging the worm gear. I pushed it down with a screw driver to secure it into the worm gear.
Finally, I didn't keep track of the cam position when I took the assembly off so I had to reopen it and check the proper orientation before putting it together. After the assembly was put back in place, the pins were not in their proper place so I had to snap the plastic cam over the pin. I am glad that I check the operation by pressing the vent controls.
It took me a little over an hour, but finding this rather simple and inexpensive fix was fantastic!
05-28-17, 09:37 PM
#19
Moderator
Oh dear ... 
here we go again ... Please please make a distinction between MODE and MIX servo. My first instinct is to delete posts .. but the author has gone through the trouble of posting.
Salim
here we go again ... Please please make a distinction between MODE and MIX servo. My first instinct is to delete posts .. but the author has gone through the trouble of posting.Salim
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