Yes. They use watch batteries.
Yes
The most common cause for a Mercedes-Benz not to start is a dead battery. Try charging the battery to see the automobile will start.
remove the manual key then remove the top of the key and replace the two batteries cr2025.
Replace the battery on your remote key. If you get the dealer to do it for you it is notoriously expensive. Did you try unlocking the passenger side with the key?
i lost my key
it won't start!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
With the key?
Yes there is ....you'll need a thin-blade screwdriver (or even a kitchen knife) to slide back the sheath on the back of the key fob to reveal the battery.
To fix a Mercedes remote, first, replace the battery by opening the key fob and swapping out the old battery with a new one of the same type, typically a CR2025 or CR2032. If the remote still doesn't work, try reprogramming it by inserting the key into the ignition and turning it to the "on" position multiple times. If issues persist, check for physical damage or consult a dealership for further assistance.
how to reset remote key fob for Mercedes SL 320
How about hooking up jumper cables, which can be done under the hood, and let the alternator of the charging vehicle provide the unlocking power? Use the metal key that slides out of your keyless remote if it has one and unlock the trunk manually where the release button is on the trunk. That's how it is on my e320 if it's the same.
Anywhere from $175-$250 from the dealer, don't buy the key from ebay.