How to Troubleshoot a Mercedes Window Switch

1. Press the correct button if the window you want to open won't open and another one opens instead. On the driver's door set of switches the top-left switch operates the left front door window, the top-right switch operates the right front door window, the bottom-left switch operates the left rear door window and the bottom-right switch operates the right rear door window. The switch on each other door opens the window on that door.
2. Release the override switch if the rear windows won't open. The override switch is designed for safety to stop children from operating the windows. The switch is located on the driver's door (or console), and newer models include an indicator lamp that will illuminate when it's activated.
3. Press the lower part of the switch past the resistance point if express opening won't work. During express opening, the window opens without you having to keep the switch pressed down. Pressing the upper part past the resistance triggers express closing.