Trunk light location
There is a predrilled hole up under the package shelf. Watch your you pull its and salvage yards for later A bodies. I've gotten several from later Valiants and such It's an extra wiring harness that plugs in between the harness that goes back to the taillights. Then you have the on-off plunger switch mounted in that little tab on the forward left trunk rail beside the trunk seal. Pull the wire off the switch and unscrew the switch, 7/16 I think. Reinstall in your car. The tab on the light socket is held on with a phillips screw.