Re: 1973 johnson 135 safety switch?????
I have a couple of them if you are referring to the ones on the engine. The switch is part # 386056. It has standard ears, so the wires just slip on with clips.
There was also a neutral safty switch on the standard 1973 and newer remote controls, so OMC did away with them on the engine on more recent motors.
Some models also had a mercury switch so that if the boat turned over the engine would stop. I don't have any of those.