Door not opening after using key to unlock

[bassinbill42]

I have a 2002 Nissan Frontier Crew cab XE V6. No power door locks nor power windows. Every door locks and unlocks properly except the front passenger door. Last week after locking it from the inside, then I returned to the truck to unlock it from the outside using my key. I lifted up the door opening latch after turning the key and it did not open up. I had to go into the opposite side, reach across and flip the door unlock mechanism to get the door to open up. Now when locking the door either with the key or the inside manual knob I cannot get it to either unlock nor open. I am also using the original key that came with the truck. I did take off the inside door panel, lubed the arms with lithium grease and did not see anything unusual or broken inside the door panel. Any help is helpful please.
David

[whomadewho]

When turning the key does the lock mechanism move up & down? I suspect the problem is the actual door lock. If the key isn't used on a regular basis over a period of time the lock assembly fails to operate freely. Take some penetrating oil and spray directly into the lock assembly, insert the key and rotate until the lock turns freely. The process maybe time consuming.

[bassinbill42]

Hi and thank you for your response. I have tried that and it does not make any difference. I had been told that the door panel will have to come off again after I reinstalled it to go to work the next day. Looks like I will have to disassemble the entire door and replace each of the plastic boots at the end of each door operation rod which attaches to the locking assembly.

[whomadewho]

Before removing the panel - open the door and take a screwdriver and move the outside door latch (next to the striker) to the close position . Next with the door open - try opening the door with the inside & and outside handles. By doing this will help determine what to focus on. The fact that the door opens with the inside handle indicates that the door lock assembly is working. If the outside door handle doesn't open the door if possible try unhooking the outside door lock assembly. Also if the truck uses a key fob it's possible the door actuator is faulty this would also prevent the door to be opened with a key.