Removing a Mercedes Benz C240 Rearview Mirror

1. Park the vehicle in a sunny location on a warm day. The heat from the sun will help warm the window and make the glue easier to remove.
2. Slide the end of a flat screwdriver under the plastic casing around the base of the mirror and gently pry the casing off. Grasp the small plastic electrical clip near the bottom of the mirror and unplug the wires from the base of the mirror. The auto-dimming feature, thermometer and compass on the C240 are electronic and you must unplug the mirror gently to prevent damage to the electrical system.
3. Hold the mirror in both hands and twist it counterclockwise to remove the face of the mirror from the button glued to the window. Insert the proper Allen wrench into the screw at the base of the button and remove the screw to loosen it from the glass. The owner's manual for the model year of your Mercedes Benz C240 will indicate the size of wrench necessary to remove the screw.
4. Draw a small circle around the outline of the button on the outside of the glass with the grease pencil. Placing the mark on the outside of the glass tells you where to install the button for the new mirror, without running the risk of erasing the mark while cleaning the glass. Mark the front of the button with a grease pencil so you don't reattach it the wrong way when you install the new mirror.
5. Spray the base of the button with glue solvent and allow the solvent to sit on the glass for 20 minutes to soften the glue. Hold a metal putty knife at a 45-degree angle against the glass and scrape the button away from the glass. If the glue is still hard, heat it from the outside with a heat gun until it has melted enough to remove the button. Mirror buttons on the Mercedes Benz C240 are made of metal and will not be damaged by the heat gun.
6. Dampen a clean towel with glue solvent and scrub away any residual glue from the glass. Coat the button with solvent and wipe any leftover glue from the button before installing the new mirror.