How to Replace a Battery on the Fob of a Mercedes E

1. Place the key fob on a table with the locking tab facing up.
2. Push the locking tab to the left.
3. Pull the metal mechanical key out of the fob housing.
4. Push the metal key into the hole to the left of the locking tab and slide it to the right to unlock the battery compartment.
5. Pull the battery compartment out of the fob.
6. Remove the two batteries from the compartment from under the contact springs.
7. Push the new batteries under the two springs with the positive sign facing up. Hold the new batteries with a clean, lint-free cloth.
8. Press the battery compartment back into the fob housing. It will click into place.
9. Reverse steps 2 through 4 to reassemble the key fob.