My rusty ford developed an annoying fault: Would lock as normal, but would not lock up ocassionally. Sometimes need one touch, sometimes four, sometimes I had to resort key.
I measured the battery, changed the battery, tried contact spray and canned air. Not much help. Sometimes worked sometimes not.
There is a plastic bridge that holds circuitboard down. Used scalpel to cut off the mushroomed heads of board stand-offs.
Micro switch was loose...looked like very little solder on the pad...bit solder and sorted!
Now the question: if the plastic standoffs fails, how to fi it. I had to cut the heads of to gain access to innards. There was left very little plastic to heat/mushroom.