I have a 1969 280SL US version. I am installing the wire harness to the motor and now am stuck on the starter.
As you can see in the photos, I have one thinner gauge gray wire (T50) and one thicker gauge red wire (T30). Along with the positive battery cable which is not in the photo.
I have my old starter out of the car so I am using it in the photos.
I know that the positive battery cable belongs on the large post on the starter solenoid, signaled by my red arrow in the photo.
I think that the thinner gauge gray wire goes on the small side screw on the solenoid, signaled by my gray arrow in the photo.
Based on the diagram I found on this site, the red wire belongs on the same large post on the starter solenoid as the positive battery cable. This makes sense to me as that red wire is connected to the alternator and is where the alternator sends its charge to the battery. That diagram is however for a 1970 and mine is a 1969 I assume that starter wiring would be the same, but I may be wrong.
However, the red wire eyelet connection is too small to fit over the large post on the starter solenoid.
I read on a forum chat that the gray wire is connected to the neutral safety switch. I checked mine with a continuity tester and it is correct.
the red wire eyelet is bigger than the gray wire eyelet one, so it would not make sense for those two to go on the same smaller side screw.
If necessary I will either drill out the red eyelet or crimp on a larger one, but I would like to know where it belongs first.
If anyone could could help me, it would be greatly appreciated.
thanks