07 SL550 won't start - starter doesn't engage
 

Hey Guys, I posted this earlier but I think I posted it in the wrong place..... anyway does anyone have a suggestion on getting this thing started? Thanks for any help!!

I have an issue that I am having difficulty diagnosing. I have 2 SL550's both 07's, a black one and a white one so it is easy to swap parts to diagnose a problem. After driving the black car for a while knowing the start battery was going bad, my wife came home with it running fine and after turning the car off it will not start... starter will not engage doesn't even turn over. So knowing that battery was bad I went to the Mercedes store and bought a new starter battery thinking that had to be the problem. Replaced it and still have the same symptom. using either the keyless go or placing the key in the ignition the symptoms are the same..... starter solenoid doesn't engage. I know both batteries are good b/c I swapped them into the white car and they worked fine..... Is there some sort of starter relay or security mechanism that prevents the starter from engaging..... I have checked every fuse in all 3 fuse panels and none are blown. Is there anything anyone can recommend that I try? Thanks

Can you jump the starter solenoid? If you can, you may find it will engage the starter. If you cannot jump it, Try swapping the one from your white car. Should be simple to do and I suspect you may find this is the issue. If not, at least you can eliminate that from the equation.

Vulcaneer, thanks for your response. The problem was a bad starter, although I have never seen a bad starter manifest itself that way. Bought a rebuilt Bosch from a local import parts store for $137 vs a "factory rebuilt" at the Merz store for $416!! Anyway thanks again for your help. BTW that sucker was a PITA the replace!!!

Thank you for coming back to post your resolution. You did very well to find a rebuilt for short money. I am sure it will be just fine.