Aileron and Rudder Trim have a limited authority over their respective flight controls. You should be able to manually centre with your feet and hands (
and go in the opposite direction to a limited degree).
The centering cams and springs will make it awkward to fly, however, because of their non-linear behaviour.
As previously stated, there are two switches per system (arm and control), so it's very unlikely that both would fail in an active position.
Unfortunately, the trim switch electrical contacts on some aircraft are such that you may only get the trim motor to stop dead in its tracks by applying reverse trim, not reverse its direction. I would still attempt to reverse it, however
