Rear Door indicated not closed in the cold....
 

We have a 2004 GX470 and the rear door light and interior lights flicker in the cold weather. Have had the dealer check it twice and still is happening. Has anyone else experienced this problem?

I have a similar problem, I have a 130lb Bernese Mountain Dog, who likes to lean against the back door while riding. Whenever I accelerate, and the pressure increases against the door, the lights come on. They turn off when the accelerator is let off. The door is fully latched, and from what I can tell, the door close switch is just not being depressed enough. I haven't made it down to the Lexus dealers to have it replaced yet.

Try this. Place a piece of duct tape over the black push switch that is on the left door jam of the rear door, so it holds the pin in. this should keep the lights off while the door is still open if done correctly. If the problem disappears, then you can tell the dealer which switch is malfunctioning, and have them repair it. If the problem persists, try each other door, one at a time, until you locate the malfunctioning switch.

door adjustment
 

this problem has haunted me for the last two winters. it only happened when the truck was cold. i left it overnight when it was below freezing and the next day the dealership found that the door needed to be adjusted and now its fine.
good luck