Your description sounds like either a faulty switch in the trunk latch or the wiring to it was damaged. All of the doors, hood and trunk have a switch in them which tells the body module that they are closed and latched securely. It turns on the door ajar light if one isn't and it will prevent the door locks from operating because one of the doors isn't closed. It also turns on the dome light because it thinks the door is open.
The attached image shows the wiring for the switch. From your description it sounds like the switch failed and not the wiring. If it was disconnected you would have the door ajar but no interior light. If it was shorted out you would have the interior light but the door locks would work. As such I would look at the latch and switch itself, they are one part and replaced as a unit. You might be able to get the lights off and things working if you sprayed the latch with something like WD40 and opened and closed it a few times but it would depend on if the switch is simply stuck or if it physically failed.
To access the latch requires removing the inner trim panel which uses push fasteners. Then the latch unbolts and unplugs. The replacement is bolted in and adjusted so the rear latches properly.
Images (Click to enlarge)
Jul 25, 2020 at 10:18 AM
