Trim not working on boat. Can someone give an idea as to what may be wrong?

This is a Mercury 50hp four-stroke outboard motor on a pontoon. We took the boat out about a month ago and everything was working fine. Went to raise the motor yesterday to run the boat for a bit and the trim did not go up or down. Tried from the button on the motor and from the switch in the boat on the throttle. There is nothing at all ...no clicks..no noises...nothing! Everything else is working and motor starts right up..the battery is fine. Where do I start to find out what the problem could be? Is there a fuse for that ? or how does the wiring work to check that? The boat is a 1995 voyager...pontoon. Bought it used and can seem to find a manual anywhere for it.... Thank You