Never thought about it too much 'til you don't have it.
1997 E350 5.4L Club Wagon XLT. Interior dome / courstedy lamps don't come on when any door open. Manual says dome lamps should come on:
1. if they are manually "rocked" to either side
2. The headlamp switch is rotated fully counterclockwise
3. any door is open
There are no pushbutton or rotary switches near the headlamp switch that "blend or hide into" the dash panel. Lamps turn on if manually rocked to one side but do not come on for #2. or #3. This tells me power is getting to them and lamps are good . Also none of the doors ajar switches turn on the lamps. Not likely all four door jamb switches are bad. Gotta be something common.
Also, the key in ignition door chime works and I can shut it off by pushing switch in door jamb so this tells me that IF this van is wired with common sense, the jamb switch provides a ground for the door ajar feature and if it's grounding for the key chime, why not for the dome lights?
Any ideas or wiring charts appreciated.