Slide issue

Broken shear bolt is my guess.
Good luck on the repair!

I had a similar experience with a Cardinal fifth wheel. One side of the slide hydraulic has the "power" and the other side of the slide is moved by a bar going over to the other non powered side. There is a pin or bolt in the bar on the non powered side that can get loose or break. I have explained this in "layman's" terms since not a mechanic. Look under the slide for the bar and check to see if bolt or pin is still there. If the bolt is missing, the non powered side will not go out. I think the bolt is a number 8 and readily available at hardware stores. Now, this may not be your problem but is the first thing to check. Also, you may have a different system such as electric/cable. If this bolt is your problem, you will have to get the slide even. Front jacks worked the same way on the Cardinal and the bolt came loose and fell out and that jack didn't go up or down. Someone with more mechanical knowledge should come along for a more precise answer.

Where would I look for this shear pin? Would it be visible without taking the cloroplast off the bottom?

Could it possibly be a schwintek system and needs to be reset or synchronized because of possibly letting off the control while in motion? Does it have gear like aluminum tracks on top and bottom of slide, outside?

Aluminum tracks would be on the front and rear slide walls.

Do your operating instructions say "Hold the button for 10 seconds after going all the way in or out" ?

It is a hydraulic system. Sorry, I should have mentioned that.