My mechanic told me it helps start your car.
For that model year there are two batteries. The largest one is in the trunk underneath the spare tire. The smaller one is in the engine compartment and is about the size of a motorcycle battery. This second battery is an emergency backup due to the fact that the braking system is electrically powered.
Trunk< under left panel>
This small battery is for the sbc braking system. Your car uses a electronic brake pump. The battery is their for a back up electricity supply just in case there is catistrofic failure of main battery or power supply to the sbc pump.
under the hood. top left
i can't detect key for satart
The keyless remote for a 2003 Mercedes-Benz S500 typically uses a CR2025 lithium coin battery. To replace the battery, carefully open the remote case and swap out the old battery for a new one, ensuring the positive side is facing the correct direction. Always check your vehicle's owner manual for specific battery information.
Where are the jump start terminals under the hood on a 2003 e320
The Battery for the Mercedes G500 is in the rear footwell. Think the hump on the floor where the passengers sit. You have to remove the cup holder (held on by 2 screws) pull up the mat on the floor (in the center) and viola -- battery. Battery has a vent hose on side.
A new replacement battery for a 2003 Mercedes-Benz C240 costs between $128.34 and $173.26. The price of $173.26 is the list price.
Waiting for the answer.
Check under the back seat.
Dead cell in the battery or something is on pulling power from the battery. Have the battery tested at any auto parts store.