My 2007 V70-R has had a failure in the right side headlamp: it is aimed very low and the diagnostic message says headlamp failure. The bulb is lit, but the aim is very low. It seems something in the self aiming feature has failed. The dealer's only suggestion is to replace the entire assembly for $1200.

Does anyone have a suggestion how to isolate the failure, and replace just the bad part(s)? There is an adjusting motor, and presumably a sensor somewhere and a controller.

 

Following yesterday's post, I made some discoveries last night.
With the headlight switch in the rightmost position (i.e., lights on in active mode), both lights aim rather low. The left one responds a bit to the high beam switch. The dashboard diagnostics says "headlight failure".

However, in the "O" position of the headlight switch after dark, the lights automatically turn on... and the heights of both lights go to normal low beam position. The dashboard diagnostic error clears. Holding the high beam switch causes both to go to high beam, but they return to low beam when you let go of the switch (normal function).

Surprise, switching back to the on position leaves the lights working normally on low beam. You can then go to high beam and both lights work. But, going back to low beam causes both lights to aim all the way down and the failure diagnostic returns.

This combination shows that the lights, power supplies, and height adjusters are all capable of working correctly. I can only assume the problem is really some kind of software or computer problem in the control system.

Had I taken the dealer's suggestion and paid $1700 ($1200 for the headlight assembly and $500 labor to install it) I suspect the problem would not have been solved.

It is not obvious where to go to find a solution. Is there any information out there on the controller and software?