1997 Ford Windstar

First, I'd check the obvious, making sure the dome light switch is in the correct position. (Make sure the switch is in auto-on, not permanent on position).

Next, I'd check the contacts to the sliding door. I think there are four of them. Disconnect the battery, get some steel wool and lightly scrub the contacts, both in the pillar and the sliding door itself. Make sure the contacts are shiny. If you don't disconnect the battery, you'll end up with some burned out fuses and perhaps some sparks.

Next, make sure the door sensors are functioning. The door closure sensors are in the door latch. Remove the interior door skins, disconnect the sensors one by one and see if this makes a difference for the dome light.