The tail light wire is always black / yellow, but that is the wrong way to solve this problem. If you can go through all that work to run another wire, why not take the easier route and find the break?
My students learned real quickly that running another wire was never an acceptable professional solution. You need to know why the original wire has a problem to figure out the cause, and if it will affect other wires in the harness. One good example is a harness that is draped over the sharp edge of a metal bracket. You can't just add a second wire because the original one will still be shorted to ground. Even if it is cut open, one end could be shorted to ground, so adding a new wire will just put a short in the circuit. How long will it be before the next wire in that harness also rubs through and shorts out? What if that happens on a dark Saturday night 20 miles from home, and the engine stalls and won't restart?
In the case of your tail lights, you also have the license lamps on the same circuit. If the splice is corroding, it will likely affect the those lamps in the near future, then you'll be back down there again. the right way is to find the break, then perform the proper fix once we know what caused the problem.
Mar 1, 2021 at 4:31 AM
