Here's the wiring diagram for some of the interior lights. The trunk light circuit is at the extreme RH side of the schematic. Even though it doesn't show in the diagram, pin A of the trunk switch should have a dark green wire running from it to connector C250 pin A (C250 is the four pin connector near the battery), and from there it runs up to a factory splice in the instrument panel harness, behind the LH side of the instrument panel for the hood/trunk/door ajar light. The splice will have a black/pink wire, and two dark green wires running into it. You'll add your new wire running from the trunk switch to it as well.