Door lock not unlocking when below 70 degrees F

[thunderX]

I've found several posts on what appears to be a fairly common problem but no definitive solution.

Some think it's the actuator, some say to simply lubricate the moving parts.

I did the latter but the door lock still does not unlock when pressing the unlock button on the key- all other doors unlock. I end up having to use the key to unlock the driver's door.

I wanted to get some feedback from those that have fixed this problem before spending a couple hundred bucks.

Does this sound like an actuator problem?

Thanks for any help provided.