One sticky door lock post in cool weather

[Muse]

Mazda 626 LX 1997 with the stock security system, and in cool weather when I hit the button on the remote, all my doors unlock except the driver's door. In warm weather it works OK. The cooler it gets the more iffy it gets until like now (days 50 and below, that's almost as cold as it gets here), the vertical lock post just doesn't get up high enough (unless I pull on it!) so I can open the door. I can open the door part way (1/2 an inch), but something catches and I can't get the door open without pulling up on the vertical thing with my thumb and forefinger that last 1/8 to 1/4 inch or so. I find myself having to open the left rear door and reach around and pull the thing up, and then the door will open. I tried spraying some graphite around that vertical lock post, but it obviously didn't solve the problem. Should I try that again, spray some type of fluid in there? Or this even fixable with a lubricant? I don't know exactly what the issue is, of course. I just assumed that something needed lubrication, but maybe it isn't that simple. I figure there must be a solenoid that gets a jolt of current and suddenly pulls a steel rod to either push up that lock post or pull it back down. It goes down all the way no problem, going up in cool weather it just doesn't make it. Will I have to take off the door panel?

Edit: [ I guess a workaround would be to use the key until I fix this. ]

Thanks for clues, help, etc.!

 

[Muse]

I'm getting some help in the Mazda Miata newsgroup, so yeah, there's hope I can fix this. Looks like the panel has to come off before I figure out what the problem is.