Door lock help

[RADDOC]

Hi there... I have a 1997 Explorer Sport. I have a situation that I've got no idea as to why it happens, or how to fix; But... I cannot unlock the drivers side door using my key. It does allow me to turn the key counter-clockwise (locking it) without issue. But when I try to turn it clockwise (unlocking it), it doesn't work.... Why? How can I resolve this problem inexpensively? Is this a common problem that many of you have experienced?
***the key does lock and unlock the lift-gate and passengers doors without problem***

Thanks for your help in advance

 

[koda2000]

typically the key's don't work in the lock because of dirt in the tumblers. this happens more often with vehicles that have remote door openers, as the keys are seldom used. in your case, as the key will lock but not unlock, my guess would be that something may need lubrication in the linkage that connects the lock to the door latch, or the latch itself. try spraying some WD40 in and around the latch mechanism (from the outside) first. use the little straw to get in there really well. it may take a while for the lube to work it's way in. if that doesn't work you'll need to remove the interior door panel and look in there to see whats happening. most vehicles just have a single rod between the key and the latch, and move a little arm up and down to activate the locking mechanism. sometimes there are little plastic clips that guide rod, these clips can break with age and cause problems.