The dome light wiring has one "hot" wire to the light, and the ground side is provided through the door switches or the switch on the light.

When the 3-position switch is in "On" position, the ground side of the bulb touches the grounded frame of the light which is screwed into the car body. (The sedan works different.)

In the center position the ground contact touches nothing, obviously.

In the door control position the ground contact touches a contact that is wired to each one of the door switches. Your symptoms are those of that wire coming disconnected from the lamp switch. Another possibliity is that all the door switches are kaput.

With the door open so the light should be on, pull outward on the button (do on all four doors). The rubber boot gets stiffened over the years, and sometimes won't allow the inside piece to move outwards far enough.

Good Luck,

Bob

:>)

PS Don Foster is right about cleaning up a 12 year old switch. It works.