What about left to right? I mean you can try reaching etc for up/down ones (eb pic) without taking your bumper off, but l/r ones are deeper inside - bolted in and under HV unit (which also serves as bottom cover) - bottom of the hl. But I don't see how l/r ones can come off/get damaged without some catastrophic hl failure. (that said - perhaps lens are pointing so far down/up that you just don't see l/r initial motion)
Also, if you have airsus - any misalignment/problem with height (wheel) sensors and your car will be in a rodeo position.

 

Yes L/R are working properly. Only U/D are not moving...

 

That's good. Really narrows it down. I think user manual shows how to unbolt fuse box (RH) and washer tube (LH) to reach backs of headlights without doing a bumper removal.
BTW don't linger on 'hate your car' - you're obviously actively trying to fix it and it is love, not hate. I'm just bitter from all badly cared for cars my eyes had/have to see...

 

Haha, nah it's just this car has genuinely been involved in a lot of ridiculous situations -- sandblasted by sandstorm, someone ran a stop sign and destroyed everything from the front fender to the rear door, debris from a truck dropping in my path on the highway with no room to change lanes, etc.

I still like the car but all the little things that have gone bad I've just gone into keep-it-functional-until-I-leave mode...

My vehicles at home get all the love

 

BTW falling hard debris from preceding vehicle is I think the worst thing that can happen. It did to me on my last LS4. Was driving from hunter road force wheel balance and was happy and careless. Next thing HUGE chunk of unmelted ice projectile did ruin my day. Torn plastic shields, dents in the exhaust tubes and more. Subframe and suspension survived tho.

 

I'd start with the suggested sensor adjustment, the little guy in the picture, not the big sway bar link. You can take it of with a 10mm and lengthen it a bit I think one side is a left hand thread so do be careful as they are aluminum and easy to shear. If you get a AFS off light, you've gone a bit too long and are outside the sensor's range.

If then diagram that the OP saw was for a vehicle that had air shocks then there would be four ride height sensors on each wheel.

 

I was reading about this on another model subforum: https://www.clublexus.com/forums/is-...success-8.html

The motors appear to function after all. There's very little movement, but today when it was dark I was able to see it move down and slightly up again when I started the car. There's just so little movement that it's hard to notice...

Will take off the wheels this weekend to check the sensors...