Yup. Break in the ground circuit. You can verify this by turning on the tail lights, then remove the right bulbs and you will see the left ones turn off.
Current wants to go through the left tail light bulb, but it cannot find a path to ground. Instead, it goes through the tail light filament, then through the brake light filament in that same bulb, through the splice, then over to the right bulb's brake light filament, then to ground. Current in the left side is going through three filaments, so each one drops about four volts, so they are dim compared to the right side.
Thursday, May 18th, 2017 AT 10:43 PM