Our Endura has also had some slide electrical issues. Most of them stem from the fact that all of the connections are under the coach, unprotected from the elements. The connectors are not outdoor rated in my opinion. I have found that all of our slide issues were fixable by disconnecting, cleaning, and reconnecting everything. It might not be your fix, but it’s free to try. There are also several posts about poor ground connections on the slide motor, but that was not our issue,
You might try using some Deoxit brand contact cleaner to assist.