How do i adjust the head lights - 2006 Toyota Corolla

Look for the little plastic star drive adjusters to adjust up and down. I use a very small SAE deep well socket to adjust mine 7/32" if I recall correctly. Look near the rear of the headlight assembly. That's where Trailblazers are (Same platform as Rainier), but I know the heads lights differ just a tad.

What is the proper adjustment/
Head light adjusters are part of the head light assembly and yes high and low beam are adjusted as one unit normally. Proper adjustment is done on a machine, at an equipped facility.

There are adjustable , How to Adjust Align and Aim Headlights and Fog Lights PERFECTLY

The front head light adjustment on a vehicle can be rather complicated insofar as the vehicle needs to be a certain distance from a wall or screen, and the right and left beams need to be adjusted to specifications. I would recommend taking the vehicle in to a garage for such an adjustment short of having the correct specs for these adjustments. A repair manual for this vehicle may have the head light adjustment specs.

the bulbs are pre-set in focus and if fitted correctly in the head light assembly they will be focused and adjusted correctly. Try adjusting the whole head light assembly by the 3 screws / adjusting knobs at the back of the assembly to aim the head lights correctly.

YES. You can adjust the head lamps as per your requirements. Look for the mounting screws on back side of the head lamps. One screw with philips head will be able to adjustable for head lamp alignment.

YOU NEED A HAYNES REPAIR MANUAL.IT HAS 3 HEAD LIGHT ADJUSTMENT SCREWS WITH PHOTOS.IT WOULD BETTER TO TAKE TO A GARAGE.SHOULDNT COST MUCH BUT GET A PRICE CHECK.THEY HAVE EQUIPMENT TO ADJUST HEAD LIGHTS.IF YOU TRY ADJUSTING THEM YOUR SELF.YOUR HEAD LIGHTS WILL BLIND OTHER DRIVERS IF ADJUSTMENT NOT CORRECT.

rtcasper Clarification Request; It is the electrical adjustment (Thumb wheel Adj on facia panel) that is not functioning not the mechanical adjustment on the head lights (Plastic cross head screw adjust L/R and U/D). The thumb wheel is usually a potentiometre adjusting a control voltage applied to the head light motor. On the Merc I can't see the motor and wonder if vertical head light adjustment is vacumme operated, where the vacumme pump is located or where i can get access to the wire loom to trace it though as I don't see how to get behind the facia. ANy suggestions as to how to get to and proove which bits are working? At the moment the headlights are adjusted to point correctly by the mechanical adjustment but this does not enable me to lower the lamps easily when I put a load in the boot.

The plastic cover comes off over the top of the head lights when you have the hood open, the adjustments are there. The screws are small.

the screws for adjusting the headights are right next to the lights, they are phillips heads and are for adjusting the side to side, 
the adjusting screws for the up and down, are on the bottom of the headlights, and they are a small hole in the grill trim, these lights need a pretty long skinny screwdriver with a phillips head