HI hope there is some one who can shed light on the problem I am having with my 1990 sl 500 which I have shipped over from the UK to australia .I think the car has been started with jump leads on route to AU .My problem is that there seems to be no power to roll bar switch and roof switch and they do not light up when operated. I have tested for a live feed to the switches and there is one. I have also carried out diagnostic test and get error codes 3/6/8/ I now need to know How I can rectifiy or test these faults. I do have extensive mechanical knowledge but need a bit of help with the electrical side of things.Also,when trying to read codes from socket 10 LED light stays on permanently. I can only read codes from socket 7.
many thanks Paul ( elv)

Your code 3 is a power/voltage missing code.
This chassis has 2 OVP units, so I would check the fuses there [ all4] first for module protection, and also check all power fuses in F1 box with a meter on each side , as sometime they look good , but have a poor connection
Those are RB codes , but you should be able to get ST codes from 10 after checking above.
Jumping car is infamous with OVP fuse short..
I returned/emailed you back the info.. check you email box

thanks Arthur for replying . my SL has the 16 pin plug ,do you know were the second OVP is I only know of the one that is located were all the onbord computers are which is just behind the diagnostic plug .I have checked all the fuses with a circut tester and all seem OK thanks again Paul