In the engine well, on the right had side as you face the car (driver's side.)
Hi there is a red plastic on the 1 pole that is positive and a black plastic on the other that is the negative
under the bonnet, its insulated with a plastic cap marked with a plus ++++++++++
The battery can be found in the trunk, under boot to the right hand side under the plastic cover. There is a positive terminal located in the engine bay on the top left hand side.
Each battery terminal will have a sign impressed into the plastic case next to it, and the sign will be either "+" or "-".
The oil filter on a Mercedes A160 is located behind the valve cover next to the fire wall. It is located in a metal cylinder with a black plastic top.
It is under the car, and it is covered by a plastic shield for protection
Using 8mm socket or wrench disconnect negative battery terminal first and then positive terminal. Then unbolt battery hold down located on side of battery near engine. Pull off plastic battery cover then remove battery. Clean battery terminals with wire brush. If bolts are corroded replace them. Replace battery, battery cover and hold down. Then put positive terminal on and then negative.
The Mercedes - Benz Plastic Cover Pulls off, to reveal the plugs, you will need spline tool to remove plug lead
Under a plastic cover located between the brake reservoir and the hood hinge on the drivers side.
You can not see the battery simply from opening the hood. But, you can still jump the battery. The positive terminal for the battery is located under a red plastic hatch to the left of the engine. Put the red (+) jumper clamp on this terminal. Then clamp the black (neg) jumper clamp on a bare bolt or piece of metal that is attached to the vehicle. Be careful of the fan blade! Connect the jumpers to the other car. Start the "other car. If possible, have someone "rev" the engine a liittle bit while you (?) fire-up the SLK.
The positive terminal of the battery will be encoded with Red color (either painted or a plastic cover that lifts off) and should also have the marking "+" on it. The negative terminal is encoded with black paint or cover and should have a "-" mark.
It should be located under the hood, in a self-contained plastic area right next to the auxilary positive terminal midway up the hood on the far right side of the engine.