Q: Trunk light stays on when trunk is closed

Hi there. It sounds like the trunk courtesy switch has failed and allowing the light to stay on as if the trunk is open. This switch is usually built into the latch assembly. It can be tested for continuity with a digital volt/ohm meter to be sure that the switch is as fault. A broken wire can produce the same concern. The wire harness for the trunk lid gets moved back and forth each time the trunk is open/closed. This constant moving is similar to removing a soda can tab; you wiggle back and forth enough and it will break off. If the switch tests good, then suspect a broken wire in the trunk lid harness. I suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts. Your Mechanic has several available technicians that can assist you with an electrical problems inspection.