Have had SC430 for over 10 years, 94000 miles. Have loud buzzer sound behind dash on startup or when key is turned to on position. The sound last 10-20 seconds and goes off. I have turned the AC off and tried different modes, no change. Everything seems to be working fine with the AC. Could this be a servo motor, the noise is not coming from the engine compartment. Any thoughts on problem and how to fix it. It makes this sound on every startup. Thanks
Larry

 

Could it be the automatic headlight leveling system, as suggested in another recent post? Possibly try turning the car on with the headlights in the off position to determine if this is what the buzzing is from?

 

The noise is behind the dash and is not coming from under the engine conpartment. The lights are fine , that is not the problem
LKB3

 

Does the auto-tilt steering wheel still fold up/down on ignition/shut down? Like a burned out tilting motor? Sorry for the simplistic guesses, just trying to give some hints to what I've noticed at startup of my car. "Buzzing" is just a very generic sound, or it a true electronic buzzing rather than a mechanical buzzing? Trying to "Keep It Simple," in the hope that it won't be something too invasive.

 

The auto-tilt etc. works fine, it is a noise much louder and seems to be behind the dash, more like a very small air compressor. When I turn the ignition key to the on position, the sound is not quite as loud, but when it started it is loud due to the stronger battery voltage I am sure. When I turn the ignition off it immediately stops and if I immediately start it again the noise starts over again for 10-20 seconds. When the noise stops it is very abrupt. The noise ONLY occurs on startup, never any other time. Thank you very much for the reply's

LKB3

 

Were you able to find out anything on this noise? My 2008 SC430 has just started doing this Electronic Buzz just like what you describe.

 

Were you able to find out what was causing the electronic buzz in your dash? My 2008 SC430 has just started doing this also.
Thanks for any direction you can provide.
Ron

 

It could be the HVAC actuators or it could be a brake master cylinder issue.
the noises are different…I will look for the HVAC actuator noise thread or video I made…let us know.

 

is it this noise?
https://www.clublexus.com/forums/sc4...l#post10933995

 

or these noises…check all of them in this link ;-)
let us know please
https://www.clublexus.com/forums/sc4...l#post10933998

 

If it is the brake cylinder, you REALLY want to get that fixed before you drive the car.

Here's hoping it is the A/C Actuator.

 

I think it's the HVAC actuators not the brakes. Comes from under the dash near the center console. I took off the panel under the glove box but replacing the actuators is beyond my skill without good video to lead me through it. Thanks!

 

Here is a BAD video u can watch. All talk, no show

There are several good videos on Lexus Blend Door Replacement, but none specific to the SC430 that I could find on youTube. If you are adventurous, you can watch them and extrapolate the replacement procedure.

Otherwise, there is no shame in taking it in. When I changed the blend door servo in my IS300, I kinda remember mumbling something about never doing it again.

 

2009 RX350. I have the loud buzzing noise coming on when I turn the key to "Run" position - without starting the engine. The locus of the noise seems to be in the dash on the driver side. It stops after about 15 seconds. Does not happen again until the engine is shut off and the key is turned to "run" position again. I tried turning the key with climate control set to "Off," Same noise. Previously I've heard different noises from MANY faulty blend door servos, but never one like this.

EDIT: It turned out this was in fact one of the HVAC actuators. It was the upper one on the driver side, on the side of the heater core housing. Basically impossible to replace without removing the entire dash. With great difficulty, I was able to ro reach up and unplug it using a pick to pop the latch on the connector. The buzzing stopped. Obviously I understand that unplugging this servo impairs the HVAC function.

 

You might want to ask the RX - 2nd Gen (2004-2009) Forum as this is the SC430 - 2nd Gen (2001-2010) Forum — two totally different models.

If you accidentally typed “2009 RX350” and meant this forum, I hope someone has possible answer(s) for you.