This sounds like you might have a short to ground before the Door Ajar Switch in your vehicle. In the diagrams down below I have included an interior lights wiring diagram with the wires and splice in question highlighted and a guide on how to find a short to power in an automotive electrical circuit. I have also included a guide for how to find a short to ground as well. Please use this guide as a reference but you are going to be looking for a short to power, somewhere the circuit is shorting to a power supply like a wire that is hot at all times. You will need to us a digital multi-meter (DMM) for this so I have included a link below for you to go to if you are unfamiliar with how to use one.
Please go through this guide and get back to us with what you are able to find out.
Images (Click to enlarge)
Friday, August 16th, 2019 AT 12:35 PM