Rear Drivers Door automatic lock not working?

Recently, the rear drivers door on my double cab has stopped working with both the drivers lock control and the remote. But all other doors are still fully functional (including all 4 windows). Using the little lock switch on the door itself still works though (currently how I am using the door).

When locking or unlocking, there is no sound coming from that door. For a while that particular door would make a slightly different sound when locking and unlocking, so looks like that might have been the sign it was on its way out?

It would seem the actuator/motor is the problem, unless there is some other culprit to look for?
If its the actuator, is the only option those $250 ones from autozone? For $250 you'd think these things would last longer...

 

Easy enough to check, put a test light across Pin 1 (Blue/Black) and Pin 4 (Blue/Red) of the Door Lock Actuator connector and hit the lock/unlock button. If the light lights up you need an actuator, if not you have a wiring issue.

 

Would this be the way to go in my case? Periodically, after stopping when I get out to open lr door the lock is engaged. I have to go to main console and hit unlock to open it. Am I possibly missing something? I know the doors autolock, but assume they would auto-unlock too.