by manually i am guessing you mean pressing the lock/unlock elec button on door.
so what are you using that is giving you problems?? the keyfob (the small remote lock/unlock that comes with the keys)
is it the factory one? did you or previous owner install a remote start or alarm system?

if you can lock it using the swith on the door then the truck is ok...its the remote that you are having issues with...unless i am misunderstanding what your saying.

 

Yes. Manually by pushing up and down on the lock/unlock switch next to the handle. I got an aftermarket alarm installed 3 years ago and havent had a problem. When i lock the doors thru the electronic lock/unlock button on the door panel it locks the passenger and rear doors but not the driver and hatch door. When i use the alarm remote it does the same thing. Today i realized that my driver side door didnt lock either so when i manually push down on the switch to lock the door i also noticed that it locked the hatch which is why im saying that the problem is coming from the drivers side door since locking the drivers side door locks the hatch

 

ok, what i would do is take the switch plate off the driver door and check for corrosion on that switch. it sounds like something is shorting out....or loss of contact.

i had a somewhat similar issue a while back...my windows wouldnt work at the switch for each door, but worked at the driver door....found out my window lockout switch was corroded and i then cleaned it up and all was good.

hopefully its something like that for you....cleaning is easier then new parts.

 

The driver side door isn't making that loacking/unlocking sound that the doors make when the doors are being unlocked/locked, if the cleaning of this switch or whatever seems to have corrosion doesn't fix it. What is the part called that needs to be fixed? The door lock switch or door actuator? Sorry for all the Q's, I've never delt with anything similar to this. Thanks

 

there is a fuse in the driver side panel for the door locks back hatch, and more, I had it go, and it would only randomly malfunction

also my back window had the latch piece stuck to the glass, and when it came loose from the glass, it would no longer latch or lock closed, eventually it totally seperated and we had to replace the back window, I still find sometimes it doesn't want to latch properly and needs a delicate touch to line everything up just right to lock