Sliding door does not lock w/ remote

My driver side sliding door does not lock with the remote. All other doors lock and unlock without a problem. I've tried the child safety switch on and off but still does not respond. Do I need to re-program the remote?

I have the same problem with a 99 montana so I'll be checking for responses here too.

I actually just fixed it! The contact plate and the little "plunger" type buttoon that contact them were dirty. I clean them with a wire brush and some Windex and it worked!