Driver's door lock

I have 99 pontiac transport and have problem whit driver's door lock.When I try to unlock door whit remote it won't do it.It does unlock other doors but not the driver's door.it unlocks manually using key and also if I try to use inside power door lock switch on either front door it will unlock all doors except drivers door but pressing that switch again on either front door to lock all doors it won't lock.Any idea what could be the problem? Thanks :confused: