How do you change the code on a Mercury mountainer?

To change the code on a Mercury Mountaineer, you'll need to access the vehicle's keypad, typically located on the driver's side door. Enter your current code, then press the "1-2" key to enter programming mode. After that, input your desired new code, ensuring it’s a 5-digit number, and press "1-2" again to save it. Finally, test the new code by locking and unlocking the doors to ensure it works correctly.