Electrical problem
2003 Ford Expedition V8 Two Wheel Drive Automatic 88000 miles

The problem started with the driver door lock not always locking or unlocking and then it grew to include the rear driver side door as well. I removed the plastic knobs from the locks and sprayed electric cleaner down in the hole with a spray tube. This seemed to fix the driver door but the rear door will not unlock or lock unless you press the button about 20 times. Any advice on what I need to replace/lubricate. Also, this expedition has a bad case of the door ajar issue as well. I have tried the WD-40 trick but it only works for a few days at best. Currently, the lights only stay on (and warning light) but no beeping.