You neglected to tell us EXACTLY what happens when you try to go up. You press the button, hear the pump run but nothing moves? Or, not a sound out of it?
I'll assume no sound at all. This would mean an electrical issue, not a fluid level issue. I assume you have a center-off switch, with momentary in each direction for up/down. If that switch has 3 wires, test the switch by swapping the two outside wires on the switch. If the plate works the same as it did before, the switch is not bad. If the direction that it works is reversed when you test, you have a bad switch.
Relays are very generic and very rarely manufactured for one and only one specific application. Every how many you have, they are probably all identical. Remove one and look for numbers. Google is your friend. You may be able to get replacements at NAPA (usually best bet for that kind of thing) or a boat dealer. (Try Mercury parts.) Replace a relay and try it out. If it still fails, move the replacement and try again, etc.