Saab key won't turn in lock

Maintenance/Repairs
1

I have a 1999 Saab 9-5. For the past 4 years I have only used the key to lock/unlock the doors. (i never liked using the fob.)

Lately, once a week I am unable to turn the key in the lock. It does not budge. Sprayed some lubricant, but no effect. It stays stuck -either locked or unlocked a few days, and then goes back to normal.

When it sticks locked, I’ve unlocked the hatch and crawled inside. I can unlock the doors then from the center console, but once I exit the car, I can’t get the key to turn to lock it again.

Help!

2

I prefer graphite powder for locks. It doesn’t hold dust/dirt/grit like a liquid can.

Is the key the original or is it a copy? If it’s a copy it could be the cause if it was just a bit off when it was cut. As it’s been worn down from use it would magnify the error.

Is it both doors acting up or just the drivers door?
It is odd in the extreme if it’s both doors. Why not open the passenger door and unlock with the button?
Better yet, use the fob if you still have it.