I did some searching, but didn't really find any issues quite like this... I have a 2005 Quad cab and the rear drivers door lock is acting up.

It will usually unlock, but if you unlock it too many times in a day it quits doing that too.. It only locks when I am really lucky. It also seems to be the loudest lock on the truck.. I always know when it doesn't lock because I don't hear the little motor creaking. I looked at the wires in the boot and they all looked fine and not kinked or anything.
Since its noisy I am assuming its just a bad lock and needs to be replaced?? Anyone have a part number for that? I was able to find the number for the front driver door, but not the rear. Thanks.

 

2005 QC rear drivers door latch assembly part number is either 55276795AC or 55276797AB

 

i had a simillar problem with my 07 quad cab. turned out to be the wiring harness to the drivers rear door. started with intermitent locking unlocking and then the window stoped working and then everything stoped working.

 

^^ Yeah but he said he checked all the wiring in the door boots.