So you can trim all the way to the trim limit. Then you want to go still higher for trailer and nothing happens when you push the second switch to go on up?
That's unusual. Generally, the trim limit switch on the outdrive fails, which disables the Trim UP button and you have to use the Trail Switch [which bypasses the trim limit switch] as your Trim UP. That's at the risk of trimming up beyond limits while operating the boat.
If Trim UP works and Trail doesn't, Trim Limit Switch is out of the picture and it's
Damage Wiring, Connector Off, or Bad Trail Switch.