Here is my basic wiring diagram for those 3rd gen aftermarket pillar lights. These i ordered off of Aliexpress and have 3 wires, one for ground, running light and brake light. For simplicity i tapped one wire from the 3rd brake light and ran it through the hatchpanel where the OEM wiring harness goes through. It was a pain to fish it through but what i did was with the trunk open, i had this one wire inside of some plastic armored tubing