The following lights aren’t working: reverse lights, courtesy lights, and license plates. I changed the bulbs and all the wiring looks okay, as far as I can tell. Also, the fuses and relays look fine. What causes this kind of trouble?
Its very possible there is a ground issue as the only thing in common with all of these lights is ground G402.The ground wires meet up at a splice point prior to the ground point. To verify this, a voltage drop test on the ground side of the the various trunk consumers must be performed. The reading from the voltage drop test should be less than .1v. A reading higher than that indicates an issue in the ground circuit. You may want to enlist the help of a mechanic, such as one from YourMechanic, who will have access to the necessary documentation and have the training and equipment to test the ground circuit and correct the issue.