Yes it could be the door jamb switches but the dome light can be manually illuminated by rotating the instrument lighting control rheostat all the way (CCW I think).
Oh yeah, definitely check the bulb in the dome light assembly.
The lens is held in the base by 4 tabs near the corners:
You must be registered for see images attach
You must be registered for see images attach
To remove it, just squeeze the top and bottom edges of the lens:
You must be registered for see images attach
When you get it off you might find a normal looking bulb or there might be a tubular type bulb - think 86 has the tube type.