Having problems with a 1985 170hp Mercruiser I/O. The Up trim is intermittent. Sometimes it will work and other times it will not. The trailer switch also doesn't work from time to time. It will go down all the time. When inop I bridge the up selenoid with a screw driver and it seems to jump start it? Then switches work again. I have checked all the wiring inside the boat and it is good. There is one slightly frayed wire going into the Trim position sender switch. Suggestions?
