I thing there is something wrong with your dealer's techs. The system works by reading the leveling position sensors on the front and rear of the vehicle, one on the right front strut and one on the left rear control arm to frame. These are simple variable resistors, like on your average radio volume knob, and compare their readings to get an idea if the vehicle is level. So if the front position sensor reads different (by a fixed percentage) than the rear then the system knows the front of the vehicle is nose down and will run the headlamp motors to raise the beams and vise-versa if the rear reads less than the front. So as you can see, in your case, if the rear position sensor is constantly reading considerably different than the front then the CEM thinks the vehicle is down in the rear (ie: loaded up with cargo) and it has compensated by lowering the headlamps. I would first check to make sure that the link bar (it's about 3"-4" long and made of plastic) has not broken on the rear sensor (or the front for that matter).... and it is a serviceable part. Normally the system is calibrated using our friend Vida, with the vehicle on a flat level surface, and the values for the position sensors are then read and stored in the CEM as a level vehicle position and the systems compensates from that 'happy zone'. It would be very rare and almost impossible that both headlight assemblies had the positioning motors go south at the same time. Of coarse a 'smart tech' would have checked ALL fuses first during any electrical diagnosis.
I have had to recalibrate these systems after a vehicle has been in an accident due to the battery being disconnected for a month or more so yours may just need recalibration as the values may have been 'lost' due to a low power mode instance or a computer hiccup. You are still under warranty till at least late 2012 or early 2013. This should not be a multiple visit repair solution...... we do have a 'fixed right the first time' guideline. If your dealer can not expedite a solution in a reasonable time (like this should have taken about 1/2 hour to figure out) then please call Volvo National Customer Service in Canada @ 1-800-663-8255 and they will promptly call your dealer and get it resolved. Good Luck.
P.S. since you are in Canada I probably know one or more techs at your dealership as I have meet most of them at one time or another.
I have had to recalibrate these systems after a vehicle has been in an accident due to the battery being disconnected for a month or more so yours may just need recalibration as the values may have been 'lost' due to a low power mode instance or a computer hiccup. You are still under warranty till at least late 2012 or early 2013. This should not be a multiple visit repair solution...... we do have a 'fixed right the first time' guideline. If your dealer can not expedite a solution in a reasonable time (like this should have taken about 1/2 hour to figure out) then please call Volvo National Customer Service in Canada @ 1-800-663-8255 and they will promptly call your dealer and get it resolved. Good Luck.
P.S. since you are in Canada I probably know one or more techs at your dealership as I have meet most of them at one time or another.
