How to Replace the Key Battery for a Tiguan?

[GemmaFitz]

First, pop out the metal mechanical key; otherwise, you won't be able to open the key casing. Press the physical button to eject the mechanical key. Turn the key sideways. At the spot marked with a red arrow (1), gently pry open the key casing by lifting part 2 upwards along the gap. After separating the 'head' and 'tail' of the key, stand the key upright. You can then lift the key cover from the gap on the back of the key. Once opened, you can replace the battery. Finally, reassemble the key.