I recently noticed that my tailgate is not locking and unlocking by using the remote as it once did. The reason I am just noticing this is because I finally put my bed cover back on. I do not have an intelligent key and only use the lock and unlock buttons on the key fob to lock and unlock the tailgate. A few months ago (which happens to be the last time that I had my bed cover on) I had some rear end work done where they took the tailgate off...Wonder if this may have something to do with it no longer locking.

Any help is much appreciated.

 

Sounds like something didn't get plugged back in. Take it back to them and ask them to look at it as the tailgate stopped locking after they messed with it.