My coach used to tell me that when the slidder doesn't work you better have a good fast ball
Most of the time folks have the opposite problem as most slides do not operate directly from the converter but are wired directly to the battery, not through the converter. When wired this way there is almost always a fuse in the positive line to the slide motor, usually located fairly close to battery. Try following the SMALL wires from the battery and see if you don't come to a fuse box.
Good luck / Skip
2011 F-150 HD Ecoboost 3.5 V6. 2550 payload, 17,100 GCVWR - 2004 F-150 HD (Traded after 80,000 towing miles) 2007 Rockwood 8314SS 34' travel trailer
US Govt survey shows three out of four people make up 75% of the total population