If a hard restore, new Screen and reseating the LCD connector didn't work, that one time it got wet fried the logic board.
I have a 5th gen. 30GB that I bought second hand for a parts machine thinking that I could get it running but to no avail. It has no sound from either port and no back light but everything else including the clicker works.
So the only thing that is going to fix it is ebay and a $65.00 board,
# 820 1975A for a 5.5 gen iPod classic/video