I realize this is an aging post, but wanted to add some info to it for future searches.
I was screwing with some things with my 96 GSX & realized my VTS gauge was showing the trim all the way up, regardless of its position. this was working fine just a month back. I pulled the VTS assembly apart & found the position magnet was very rusted, In fact, I'm really not sure where it even went when I cleaned things up. I stopped at my local hardware store this morning & picked up some small neodymium magnets. I stacked two of them in the magnets original location, & tried it out. It worked perfect for the gauge when I tested it, 167ohms up & 24ohms down, so I put everything back together.
To my surprise it would not actually go all the way up or down. This was the moment that I realized there are limit switches in these VTS assemblies. Previously mine would just spin until it would reach its mechanical limits, & stall the motor. I thought that was normal & the gauge was working at this time.
It turned out my problem was the magnets i used were too strong, & it would stop the motor before it would get to full travel. I took it apart again & removed one of the two magnets I had just installed, & it now works just as it should.
I never knew these VTS units had limit switches, & I learned something new today.