Murphy’s law said...
 

Your driver side door lock will fail at the begging of the work week when you are 25 miles away from home! Luckily I had some string long enough to tie the door handles inside and limp home. At first I thought that the lock has frozen due to prior rains and now freezing cold but WD40 didn’t help.

Fortunately it was easy to remove the lock assembly without having to remove the door panel. Close inspection revealed a broken spring. I needed my car next day so my options were limited. Taking it apart was a bit tricky but it is possible to remove the broken spring without taking the whole lock apart. I made a new spring from .053” SS fishing wire and now it works like new. Total time about 2 hours.