I have a 1995 Larson 174 I/O with Mercruiser 135. Last weekend (first time on the water this year) a peculiar problem developed--- the power trim button works when lowering the motor, but only the "trailer" button raises it. Weird! Could it be a solenoid (I think there are two- one for up and one for down?) or something in the trim button/switch itself? Any ideas on how to troubleshoot would be appreciated! 