i was driving today and my power locks were making noise like they were locking unlocking etc. now my locks don't work they make a sound like they work but they don't so how do i fix this and how do i lock the back door please help me this happened once before and then it just started working again

 

You could have a power lock switch flaking out due to a faulty switch or corroded contacts. It could also be a bad RKE module if you have remote keyless entry.

If you remove the 'pwr lks' fuse, the rear hatch will either be locked or unlocked, whichever state it was in when the fuse was removed.