You actually only change the bulb. They are held in harnesses inside the hood, just behind the actual headlights. Once you start tinkering with it, you can see how it works. It's easy to change the bulbs in a C-Class Mercedes.
Bring it to the dealer!
Acquire a new headlight. Take old headlight out. Place new headlight in. Voila
Mercedes-Benz A-Class was created in 1997.
Remove the wiring harness from the back of your 2007 Mercedes-Benz headlight. Remove the headlight retaining bolts. The headlight will come out. Reverse the process to install your new headlight.
Mercedes-Benz
Yes, the Mercedes Benz GLA did evolve from the A Class.
Mercedes-Benz R-Class was created in 2006.
Mercedes-Benz C-Class was created in 1993.
Mercedes-Benz CL-Class was created in 1998.
Mercedes-Benz G-Class was created in 1979.
Mercedes-Benz GL-Class was created in 2006.
Mercedes-Benz CLC-Class was created in 2008.