I had to replace one of the relays on a friends motor couple years ago. They are made in one piece and has a sliding contractor inside. When activated it slides leafy or right depending on direction. Should be mounted on very front of engine down low almost where you would think a carb would be. I have also had to replace brushes on a couple of Yamaha trim motors. They seem to be bad about carbon from brushes gumming up the holders and not letting them touch properly. You might try this, get a soft handled large screw driver and lightly tap around on motor housing while activating switch sometimes that little vibration will shake them loose if that’s what it is. But like said before first thing is check power and if not mistaken there is a fuse in a harness on left side of motor that is for trim.
Proud Member of Team Geezer
Charlie Weaver USN/ENC 1965-1979