Mercedes-Benz GLK 300 4MATIC 2012 Owner's Manual page 83

Key
80
Repeatedly tap the key against your palm
X
until battery = falls out.
Insert the new battery with the positive ter-
X
minal facing upwards. Use a lint-free cloth
to do so.
Make sure that the surface of the battery is
X
free from lint, grease and all other forms of
contamination.
Insert the front tabs of battery compart-
X
ment cover : into the housing and then
press to close it.
Insert emergency key element ; into the
X
key.
Check the function of all key buttons on the
X
vehicle.