hey guys, I have the similar problem. SLK230 2000. It won't start. I checked the battery and it is OK. (Sometimes when I jump it up, it starts that's why I thought it was the battery). When I turn the key I hear little click, but the starter is not working at all I think. Any suggestion what this click is? It comes somewhere next to the air filter. Thanks in advance for the help!

 

Well they though they fixed it with dirty contacts soemehere. Got the SLK home for the 3rd time and went to start it an hour later - no joy again so back to the Auto electricans again sigh
This time they think its the ECU so have yanked it out & sent away for repair