Not sure about the trim limit switch, but the Trim sender can be dismantled, the wires unscrewed (ring connector on wire ends) and replaced, although of course the trouble could be in the wire itself, or it's connection into the loom within the boat.
I think Matt recently bought replacements for his Formula, so he may know of a good/cheap source. ...Keypart maybe ??
"I Agree with everything you say really!" - John Cooke to Jon Fuller - 26-01-2013