Pat, I have had some trouble with the trim tabs in the past, but it was due to a broken line. However, the way I found and isolated the problem was simple.
First, I must remind you, you and I both have 2005 25's. So, I would think they are similar. My first clue that something was wrong was when I couldn't get the boat on plane. My next clue was that I have a indicator just below the up/down switches which shows me the tab position, all through the range. So when the labs failed up, the lights didn't light indicating "UP". In addition, whilst Judy looked at the tabs, over the rear, I tried to make them go down. And I failed; they didn't move. And last, after I added fluid, I could see where it was coming out of the broken line. Cut through by the spare propeller.
So take a look at what the tabs are doing before you fix them. They may be alright and the boat is overloaded and the prop was broken. Check first.
Boris