How To Put A Battery In A Car Key Fob. Mazda Cx 5 Key Fob Battery Replacement Diy. Learning how to change the battery in a VW key fob isnt difficult but it is important to know what kind of battery you need.

Insert the key into the ignition again and then immediately remove it. Make sure the positive side faces downward. Replace the circuit board on the keypad.
Replace the circuit board on the keypad.
If you are not sure what your key fob requires the following information may help. Check the fobs plastic for a diagram showing how to install the battery. You may need to lift out the circuit board to reveal the battery. You do this by inserting the end of the screwdriver into the side of the key where the key blade normally rests.
