We also had that problem on ours. Unfortunately, the solution wasn't as simple as a fuse or in-line reset button.
On one trip after setting up on a slightly unlevel spot, we had difficulties hooking up to the hitch. We used the button to go up and down on the landing gear quite a few times and eventually got it to latch. When we then went to unhook, the landing gear wouldn't go down, so had to lower them manually.
Like you, we checked the fuses, they were all good. It took awhile, but after looking for about 2 hours, found the 12v supply wire that went to the switches ( on ours the switches are inside the storage compartment), had burned through. I repaired it, and really wondered why the wire burned up before blowing the 40 amp fuse. I think there were 2 reasons: 1. the wire was probably hooked up with a poor connection or the wire was partial broken and 2. Keystone uses a foam to hold wires in place and seal the switches and hold them into place and this held the heat on to the wiring. A thought at first, it may have been a problem to start with, so someone ingeniously thought to replace the standard fuse with a 40 amp one, but it looks like that is the defined size.
Hope yours is simpler than this!