DIY Cost: $ 0 Est. Time: 1 - 2 mins Difficulty: Very Easy Summary Step-by-step instructions on how to adjust the side mirror on a 2016-2020 Kia Optima. Procedure Go to the driver's seat and turn the key to accessories or on position. Locate the side mirror switch on the inner door panel of the driver's door. Click on the left or right button to what side mirror you want to adjust. Push on the button with arrows to adjust the side mirror.