| The internal light and the electric window regulator may be two separate problems, but could be related. Don't be surprised if these are not related. The simplifed checkout procedures found in repair manuals may indicate a bad switch assembly - but don't believe that right-away without further checks. Sometimes, the problem is broken wires in a boot going from the door to the body. This bundle flexes each time the door is opened and wires have been know to part inside their insulation without breaking the extruded insulation. Such breaks usually happen with the driver's door, although the other doors are not totally immune. The driver's door has the big bundle. Remove the switch assembly and check it for continuity in all switch positions before replacing. Hopefully, John_G will chime in and tell us more. He knows about the various methods that Ford uses for controllng the interior lamps | 
