Open up the front compartment. There should be an electrical looking panel and a bunch of wires, probably on the right hand side of the compartment.
That panel should have a bunch of wires connected to it at screw terminals around the perimeter. The panel itself is likely potted with an epoxy of some kind. That panel is the master control unit for the remote system for all the slides and landing gear.
On some of the wires connected to the panel will be inline fuse holders. Kind of looks like this but could be any color on any color wire:
The one in this pic is missing the fuse. Pull out the fuse and look at it carefully. If it is blown, the center portion of the metal imbedded in the plastic will be literally blown away. If it is blown, replace it with one of the exact same size and amp rating. These fuses are available in any auto parts store. Places like WalMart will have them in the automotive aisles, too.
FWIW, these fuses are used throughout our Keystones. I suggest you make a survey of your trailer and determine what size and amperage fuses are used everywhere and purchase some spares.
There are only two sizes of the mini fuses used these days. ATM is the smaller. ATO/ATC is the larger. Depending on where you buy them, they may only have ATO or ATC - either is OK as they are interchangeable. Most of our cars and trucks use the same fuses these days.