How do I find out what's failed in my remote?

I accidently washed this remote as it got mixed up with my sheet, it has 5 buttons. Head up, down, home, and foot up, down. Only foot down is working. I cleaned off the minor corrosion, but I didnt find any broken traces or anything obviously blown, but im not sure what my voltages or resistances should be. This remote is 270$ new, so any help is appreciated!