Key fobs come in a variety of styles depending on the type of car you drive. Car manufacturers use the key fob to set their models apart from other automakers. Key fobs can be set only to lock and unlock your car, or they can come with lock, alarm and remote-start capabilities. The key fob button is attached to your car's ignition key. With everyday wear and tear, it is possible you will have to replace a key fob button at some point.
Remove the battery cover on the back of your key fob. Take the battery out. Use a small screwdriver to remove the screws on the back of the key fob. If there are no screws, use the screwdriver as a pry bar. Slide the head between the seam on the side of the key fob and use leverage to snap the sides apart.
Separate the two sides of the key fob. Notice that the back side holds the circuit board, while the top holds the buttons in place. Pop out the button or buttons that need to be replaced.
Insert the new button into the hole on the front of your key fob. Make sure that it is in correctly and facing the right way.
Match up the two sides of the key fob. Check that the buttons are still in place. Push the key fob back together. Replace any screws.
Reinsert the batteries and replace the battery cover. Test the key fob to ensure that it works correctly with your vehicle.