1. Locate the battery. The battery is found under the hood, on the left rear of the compartment (as you are facing the Mercedes).
2. Remove the battery cover panel. It's black and will have instructions printed on it regarding the proper maintenance intervals for the battery. Using a flat screwdriver, remove the screw on the top and completely remove the covering panel.
3. Detach the negative battery cable. The negative cable will be marked with a minus sign. Using a 10-mm wrench, loosen the bolt that closes the clamp of the negative cable around the negative battery lead.
4. Detach the positive battery cable. The positive cable is marked with a plus sign.
5. Pull the old battery from the Mercedes's battery storage slot.
6. Clean the connection clamps of the battery cables. Make sure that the rings of the connectors are free of any rust or other impurities by brushing with a wire brush.
7. Place the new battery in the battery slot. Make sure to keep the now-disconnected battery cables out of the way.
8. Connect the positive battery cable. Place the clamp around the positive battery lead. If you are not sure which cable is positive and which is negative, remember that the negative cable will be connected to the Mercedes frame or another part of the chassis. The positive cable will be connected to the fuse box or the starter. Tighten the clamp around the positive lead using the 10-mm wrench.
9. Connect the negative cable to the battery's negative lead. Place the clamp around the negative lead and tighten with the 10-mm wrench.
10. Replace the battery cover panel. Replace the battery cover panel screw and tighten with a flat head screwdriver.