Have you verified it's the switch? I am assuming the drive won't trim up and or down, correct? This is seldom the switch but instead the trim limit switch on the gimbal ring or a bad soleniod.
If you can provide details of the issue better help will be provided. i.e. drive won't go up, however does go up if trailer button is pressed. This would be a trim limit switch on the gimbal ring. or drive sometimes works, most likely a bad soleniod.
1997 2400 SCR
5.7 Vortec / Bravo 2