Find a vacant parking lot (preferably not on a slope) that you can park facing a large building.
Turn your headlights on.
Under the hood of many vehicles there are adjustment screws above, behind, or near the headlights. You may need a special and/or extended driver for your model.
Your left headlight (from driving position) should face slightly toward the right in order to avoid blinding oncoming trafficand your right headlight should face directly forward (centered--not left or right).
I assume you mean the angle of the headlights and not the brightness. On the headlights themselves are Allen screws with measurement markings and angle degrees. Loosen Allen screw and move bolt forward or backward to change angle.
It has 2 adjustment screws, one controls the angle in/out and the other controls angling up/down.
The 2006 Chevrolet Suburban has a 25 degrees angle of approach.
The 2009 Chevrolet Suburban has a 16.9 degrees angle of approach.
The 2007 Chevrolet Suburban has a 16.9 degrees angle of approach.
The 2004 Chevrolet Suburban has a 22 degrees angle of departure.
The 2010 Chevrolet Suburban has a 16.9 degrees angle of approach.
The 2002 Chevrolet Suburban has a 22 degrees angle of departure.
The 2011 Chevrolet Suburban has a 16.9 degrees angle of approach.
The 2005 Chevrolet Suburban has a 25 degrees angle of approach.
The 2014 Chevrolet Suburban has a 16.9 degrees angle of approach.
The 2009 Chevrolet Suburban has a 20.5 degrees angle of departure.