Welcome to the forum.
In QT's 1 & 2
you will find all slide information for slides
The lock controls the operation of slide and if the contacts have gotten water in them you need to clean locks or replace them. There are threads for locks and what people have done to fix them and spec by Newmar on how to trouble shoot them.
All the links below in my signature have other info for your Newmar.
QT's # 3
has PROBLEM SOLVERS that may have other slide info for you.
Here is a link
to TSB's for your coach and you can get brochure and owners guide in it also plus other information.
I have givin you some of the links for your problem.