and i assume the switch doesn't work in either direction?
Troubleshooting 101: Can you unscrew the switch and check the wire behind?
2: Can you identify where the wires go? They would be connected to some sort of controller, which you know functions because the remote worked.
My first suspect would be the switch itself being bad. Second suspect is a wire is loose behind the switch or at the controller. there could even be an inline fuse.
Keystone also has an owners forum, where you might find an answer. It's here -> Fifth Wheels - Keystone RV Forums