Is the slide not working now? If you can get it to work by resetting the controller, hold the retract/extend rocker switch down for several seconds after the slide stops moving. This will sync the motors. Out of sync motors can show the fault you are seeing.
1998 Min Winnie, 2000 Winbago Journey, 2015 ACE 29.3
2016 Thor Miramar 34.2