I bought a new doorjam switch and harness. Old plug was 2 wires , new one has 3. When the door is closed the hot wire is hot. When the door is open , the hot wire is dead. When I disconnect the black wire from the green hot wire, the green wire is hot. Please advise oon how this is to be wired / Thanks

 

My recollection .... was fubar

 

https://www.ford-trucks.com/forums/1...00-1973-a.html

All you’ll ever need to know about dome lamps. The door jamb button is switched 12V power, that’s it. The light is grounded by a screw under the headliner. You don’t need the third wire on the switch.