'62 Valiant, door pushbutton inoperative

No, it's the passenger-side door.

Here's an update: I removed the interior door panel and took the car to a shop of a locksmith who has repaired auto door locks for me in the past. He observed the latch's operation carefully and diagnosed it as a problem with the lock assembly itself. So today I removed the window regulator, the remote control assembly and the lock. Tonight I'm soaking the lock assembly in mineral spirits to clean it up, and tomorrow I'll take it back to the locksmith for a diagnosis. I'll let you know more when I find out.