I am trying to solve a minor problem with the interior lights on a friend's euro '85 280 SL. It has two small square lights in the windshield header and one in each footwell under the dash. When a door is opened, the footwell lights go on, but the windshield header lights do not. There is a 3-position switch in the center of the dash which is supposed to have always-on, on-when-door-open, and always-off positions (I think). When the switch is at the always-on position, all four lights illuminate. Aren't all four lights supposed to light when the door is opened, if the dash switch is in the on-when-door-open position? If so, what could be causing the windshield header lights to light only when the dash switch is in the always-on position? Thanx in advance for any help!!