To replace the battery in your remote car key, remove the cover from the back of the remote, take out the old batteries, and replace them with new ones. Replace the cover of the remote, and test to make sure the unit functions.
Begin replacing the batteries of a car remote by taking the remote out of its key ring. This makes the remote's cover more accessible. To remove the cover of a car remote, check if there are any screws in the back. If so, undo the screws using a screwdriver. If there are no screws, check if there is a notch on the side of the remote. Insert a coin into the notch, and pry open the cover of the remote to expose the batteries.
Before removing the old batteries, note their orientation in the compartment. Use your fingernail to pry the batteries out. Don't use a metal edge to remove the batteries, as it could damage the electronic parts. Avoid touching the circuit or terminal in the battery compartment. Place the new batteries in the remote, keeping their orientation the same as the old ones. Review the manufacturer's instructions to ensure the new batteries are placed correctly. Screw the remote's cover shut, or press it into position. Finally, check the unit for proper functioning from the usual distance.