XH door locks

[soco3594]

Hey guys. I am having alot of trouble with the door locks on my 96 xr6 ute. The passanger side door lock seems to be the problem because the handle is very stiff and I can't lock the ute at all. When i press te button on the key the locks go down then come straight back up. The same happens if I lock the drivers door using the key and I can't seem to get the passanger door to lock.

Has anyone had the same problem and if so what did u do to fix it? Is it simply a case of replacing the lock?

cheers