If you have the 12v locks at either end of your slide, the Actuator contacts in it have become rusty and slide will not move. You can gently tap the box at both ends may free up the rust and slide may move.
Within this link you will find slide section and
Slides the Good, Bad and Ugly thread it will explain the Actuator, you maybe able to clean with contact spray or change it, look for that thread in
this link.
Welcome to the forum and irv2.