Our 2017 RX has AUTO lights, but for some reason they no longer dim, they are on brights all the time they are on. It is my understanding to set the AUTO you twist the switch to AUTO and then flick it down to bright and it is supposed to auto dim when meeting another car. Ours doesn't. They auto turn on when dark but are on bright all the time. Is there a sensor that might be dirty or do we have a "computer" problem.

 

Is it "automatic headlights" or "automatic high beams"? They are two different animals.

From your description, it looks like your Lexus has "automatic headlights" but not "automatic high beams," and the "high beams" switch is turned on. Pull the headlight switch stalk back toward you to see what happens.

 

On your dash there should be a "bubble" looking bump maybe about the size of a large gumball. On my IS its closer to the windshield and on the passenger side. Take a dry microfiber or "swiffer dry wipe" (thats what I use) and gently clean off the dust and dirt... Clean your windshield (outside and inside) just for good measure with whatever windshield cleaner you like. This should solve the problem immediately. If it doesn't, then the sensor is faulty.

I clean that sensor off about twice a month.

 

I think this is the light sensor for auto headlights (maybe also for other things that depend on day/night setting). The sensor for auto high beams, I think, is located behind the rear view mirror.

 

You also need to select the "Auto Dim" feature on the panel of switches on the dash to the left and below the steering wheel. You will see a "Blue" headlight on the instrument panel when it is set up and operating.

 

https://www.google.com/search?q=2017...id:180pmWjP_Vw

 

No, just a cockpit problem. Press the Auto High Beam button to the left of the steering wheel.

 

The turn signal stalk "Auto" position is for the Low Beams and various marker lights.
Controlled as described above by the dime sized black dome on the dash top. When it is
dark enough or you twist the Headlight Control upward you will see a Green "Lantern"
icon on the Instrument panel.
"Auto High Beams" on 2016 and newer RX's have a button on the left lower dash that
appears as a light with "Auto" superimposed. Leave this pressed in and when the Low
Beams are on you will see a second Green Lantern that also has the word Auto. When
you are driving over 15 MPH and are alone on a dark road the High Beams will come on.

 

Thank you all. It was working correctly and just stopped. I will investigate and I'll bet it is the button to the left of the steering wheel. I am always pressing buttons trying to find the "hatch button" in the dark.

Bill

 

The heated steering wheel button is just below the Auto High Beam button.
Too easy to press both when shivering and wearing mittens...

 

Also, check your settings when you get the car back from service appointments, the techs seem to turn mine off each time after a service appointment.