Locks on 1997 Mercedes-Benz E420

My doors are not locking automatically; is it because my key remote is losing power? If not, why aren't they locking and where is the lock for them inside the vehicle?

Asked by for the 1997 Mercedes-Benz E420
2 answers
you need a new battery for the keys.
The manual inside lock pbutton is on the front dash. also check the #6 fuse under the back seat on passenger side next to the battery.