Might try hooking up the hand crank and see if it will extend manually. Doubt if there is more than one motor though. Look around carefully to see if there is any sign of water intrusion. Sometimes when things get wet they swell and can bind a slide. Hopefully it is something simple like a broken gear etc.
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
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