1967 was a change over year so that means this could be a 111 or a 108. Mercedes had some left over 1966 250s cars and they sold them in the US as a 1967 once the calendar turned.

I have a wiring diagram for a 111 and I could sort through it. If your car is a 111.

I think the first official year for the 108 was 1968 but they did start in Europe in 1967.

Anyway, let me know and I will help if I can.