seany

I just picked up 2009 GS 350 AWD but can't figure out what that black sensor is right under the brake light in rear windshield.

I want to tint my windows. Does it matter, if this sensor is covered?

Teocali

This sensor controls the ECD (Electronic Chromatic Device) built into the instrument panel, which changes glass transparency depending on exterior light conditions. A tinted rear window will probably cause your dials to dim.

TWong350

iTrader: (8)

Yep, I believe that's what it's for as well.

BTW, welcome to CL, Teocali!

Teocali

Thank you, TWong350

ferrerski

thank you - i was wondering the same thing

GS350Lexus

iTrader: (5)

That sensor as i remember is for auto headlights and the gauges. I have a 20% tint all around with no issues covering that sensor.

AustinSBP

it cancels itself out depending according to how dark your windows are .... in other words just tint them.

seany

I figured the sensor for the auto headlight was in the front on dashboard like the most cars.
Does the manual state what this is for, since we have 2 different answers here....

Teocali

The headlight sensor is indeed on the dash.

Page 195 ('10 GS 450h owner's manual) photo taken.

seany

thanx for the confirmation. so, back to the original question.... what is that sensor or is it not used in US models?

GS350Lexus

iTrader: (5)

Well by the picture above it clearly states Headlight Control Sensor, it turns on and off your headlights in the car when it is left in auto mode.

sprtdsgnGS

He's asking about the sensor on the rear windshield, under the center brake light

CAK 500

This is the correct answer, but tinting will not cause you dials to dim. If anything, it's the opposite. The brighter the light hitting the sensor, the more translucent the glass over you instrument cluster becomes. Same principle as your rear view mirror. Electrochromic glass.

If you want to see how it works, have someone shine a flashlight into the sensor and watch the glass. It gets slightly translucent/bluish. Truth be told though, it's barely noticeable and definitely won't be affected if you tint your rear window.