After researching at least 100 different places and tracing wire schematics, I'm pretty much defeated on this. Hopefully someone has seen this issue before.

Under normal circumstances, a person can simply turn on the headlights by turning the headlight switch to the "On" position when the car is off. It works this way on my other three Lexus models (LX, SC, RX). However the headlights only come on when the car is running and the headlight switch is set to the "On" position.

What about in the "Auto" position? In the "Auto" position, all the beautiful IS300 amber interior lights, park lights and tail lights come on as normal. However the headlights do not.

Here are the actions I have taken thus far with no success:

• Checked personalized settings within the Techstream app to see if the headlights were restricted to the IS300 being on/off. No options there.
• Checked all fuses in all three locations. None blown.
• Replaced headlight relay.
• Replaced the Light Control Sensor.
• Replaced both bulbs and ballasts.

My next option is to try replacing the headlight switch. However I'm somewhat reluctant as all the other lights come on except the headlights.

Any ideas?




//Beau