Electric elevator trim switch Failed

[IvanP]

A short in the trim switch wiring or failing microswitch could be the source of your problem. I had similar issue on my plane, but fortunately did not fry the A/P board. There are 3 micro switches wired together in a really confusing manner in the little gizmo on the yoke. Real b**&^ to work on  . The original complete switch is hard to find and pretty pricey (last I looked it was around $1,200). The good news is that the individual switches can be sources relatively inexpensively from Mouser and other sources and with little patience and soldering skills the trim switch can be rebuilt by your hangar elf.