As long as we're reviving this old thread.... here's my 2-cents worth.
I have a '95 900 ZXI.
It's trim system failed.
I removed the system, plugged the hole, and fabricated a fixed angle bracket to hold the nozzle in the neutral position.
It runs great!. I shift my body position fore/aft as needed to control porpoising, or other needs. I wouldn't recommend buying new parts... not worth the bother.
Some owners have been able to open the boxes, clean & dry the components, and get it working again on-the-cheap.
Incidentally, the '95 are not true KATS systems. They don't have the automatic feature. You just press the up/dn buttons till the nozzle is where you want it. Therefore they don't have quite as much wiring & sensor problems.