Welcome to iRV2 .
You problem is best described as an intermittent open circuit .
Shorts blow fuses .
You need to investigate , how Fleetwood routed the 12 volt wiring into the slide , because the slide movement is causing a wire or wires to bend and separate.
On a lot of slides the wiring is below the floor and supported by an hinged or flexible framework . The wiring runs from a junction box in the basement under the main floor to a second junction box in the slide wall .
You problem can be, a loose connection , in either box , or the wire as it is flexed during slide movement .