How do you replace side mirror 99 Mercury Cougar?

To replace the side mirror on a 1999 Mercury Cougar, start by removing the interior door panel to access the mounting screws of the mirror. Unscrew the old mirror from the door and disconnect the wiring harness if it's powered. Install the new mirror by connecting the wiring (if applicable) and securing it with screws. Finally, reattach the door panel, ensuring all clips and screws are fastened properly.