Tilt problem.

[THEFERMANATOR]

It's most likely a relay problem, but it could be either one. Even the one that trims it down could be bad. The relays ground both wires to the trim motor, and when you hit the button the corresponding relay switchs to power while the other stays grounded. It's a fairly simple system once you have a book and diagram to see how it works. Another thing you do is have somebody hit the trim button while you see which relay won't click.

But remember that if you remove one of the relays, it won't do anything. They BOTH have to be in place for the trim to work.