Volkswagen cars, vans and SUVs come with handy key fobs that feature a flip-out key and buttons for keyless entry. These key fobs are fitted with little batteries like those used in watches. Like any battery, VW key fob batteries sometimes die and need to be replaced. If your key fob doesn't seem to be working very well lately, or if it doesn't work at all, it may be time for a new battery. Instead of taking the key fob to a VW dealer, save yourself some time and money by replacing the battery yourself.
Take the key fob in your hands and pull it apart. It should come apart in two halves: the half with the buttons on it and the half with the key in it. It may be necessary to pull rather hard.
Take the half with the buttons on it and pry it open using your fingernail or another thin object (like a small flathead screwdriver). You should be able to see a seam where the plastic will separate.
Pop out the battery using a fingernail or a small screwdriver. The battery is the silver round object sitting in one half of the key fob.
Insert a new battery (type CR2032) into the battery slot. Make sure the positive side (+) faces the correct direction, which should be specified somewhere on the inside of the fob.
Put the two halves of the button portion of the key fob together by lining them up and pressing firmly. Connect the key portion and the button portion of the key fob by inserting the button portion into the slot of the key portion and pressing firmly.