There are only two ways you are going to move a slide in.... or out... if it is not operating properly.
You can use the Electronic Manual Override option or you can disengage the motors and attempt to push the slide in with several people (not an easy task).
Below are the LCI instructions that cover most Schwintek slides for the two procesures.
If you are out of warranty, I would seriously consider replacing the Schwintek Slide Mechanism with then Vroom Slide System. I had the Vroom Slide System installed in my '20 Magnitude SV34last October and it is night and day in terms of operation and reliability. It will cost you ~$3000 but it will the best investment you can make.
The Schwintek Slide Mechanism is a very poor design for a heavy, full-wall slide. I have read several people spend $1500 - $5000 to repair their Schwintek Mechanism only to have more problems. It is throwing good money after bad. Have the Vroom System installed and never look back.
You can watch this video for more information....