Latest on HID headlight aim problems

We've been having problems with our headlight aim for almost ten
months (2004 BC).

The first thing that happened is one night the lights were aiming
insanely low. We brought it in to the dealer and they totally blew us
off, so we went to a different dealer.

That dealer admitted there was a problem but (I think) only "fixed" it
by changing the mechanical aim point (upwards), because a couple of
weeks after the "fix", the headlights stated pointing way high
(i.e. non-highbeams were much higher than normal highbeams would be).
My theory was (and is) that the sensor started working (somewhat)
properly again and since the aim point had been raised, everything was
high.

The actual height would change from day to day. And some days it went
back to "normal" (probably because the sensor stopped working again).
As fate would have it (boo) the night before we were having the car in
for the 15K service, the aim went back to "normal" and so the shop
refused to investigate further. Of course, two days later it was back
to being way high. Time passes.

In the past few days the lights got truly, insanely high and we
brought the car in this morning. Either we got a different tech or
the dealership has had more cars in with this issue since the last
time we were in, because the tech told us that (a) he's seen a number
of cars with the problem, (B) Toyota knows there's a problem, and ©
he's been told that when this happens the sensor should just be
replaced. He also told us that a classic sign of the problem is if
you turn on the lights, get a bunch of people to sit in the hatchback
area, and see the lights move up (they shouldn't move when you load
the back).

So tomorrow we get a new sensor. Am keeping fingers crossed.

 

We had the sensor replaced today. According to the tech, it was "incredibly rusted and corroded". He also said that Toyota has redesigned the sensor units to be more corrosion-resistant.