I recently bought a boat 1993 rinker 236, 502 mag bravo outdrive. All the gauges work except for the trim gauge, also the trim up switch doesnt work where your thumb would be on the throttle. But the trailer switch just below that works so i have been using that to trim up. The gauge always reads that the outdrive is down all the way. What should i check for first with the gauge, also can i just buy a new trim switch to fix the one on the top of the throttle?