What are dual beam headlights?
Car headlights have to be able to "dip" so as not to dazzle oncoming traffic, they therefore can switch between a "high" beam and a "dipped" beam and thus have a dual beam.
Need to specify which headlights you have... you either have the dual composite headlights, or you have the sealed beam headlight. In the case of the former, you rotate the harness 1/4 turn counterclockwise and it pulls out. You just replace the bulb. In the case of a sealed beam headlight, you have to replace the entire assembly.
I know that if you move the turn signal lever ( which is part of the multi function switch ) away from you it turns on the high beam headlights and if you move it towards you , you only have low beam headlights ( and if you pull the turn signal lever all the way towards you and then release it the high beam headlights will flash each time you do that )