Dear Mohan
I have used the wiring diagram published on this site for model 280SL for all the 250SL projects that have passed through my hands. If the car is late 67’ could match all the things that were common on 280SL.
There is no difference at diagram level for cars that are RHD or LHD, since the wiring diagram does not show how branches are formed or the cable lengths.
What I can tell you is that RHD harnesses are more like the mirror image of the LHD with some exceptions:
1. The connection for the REAR harness is on the left fender, opposite of what you will have though if you stick to to mirror like idea. This was done in order to keep using the LHD standard REAR HARNESS on RHD cars.
2. The cold start mechanism relays are on the left fender. This for space reasons, and therefore there is a cable branch coming out of the right firewall hole coming directly to the left side of the car having all the signals for those relays as well as the coil resistance line and left fender headlight assembly.
3. Total travel of T30 lines is shorter. This since the alternator T30 cable is coming out from the unit at front right side directly to main light switch also on the right side of the car.
And many many other differences.
Your car may have the cold start logic of a 280SL or 230SL which are different. Only by looking at your harness you will know. 230SL has two relay terminals, but one of them has only three prongs connected since that is for a 1 second timed relay. If both of your relay connections have 4 prongs then you have the more modern approach implemented on 280SL cars.
Best regards
Eng. Leonardo Peterssen
Www.Wiredoktor.com
