How can light bulb wiring be damaged?
Your car is as much electric as it is mechanical. Wiring harnesses snake around the engine compartment and throughout the interior of the car. Most of your accessories run on electricity, and even a motor needs constant voltage to run. Your headlights are definitely powered by electricity and this is provided by the wiring harness. However, light bulb wiring can be damaged in several ways.
Rodent damage: One of the most common (and most unexpected) sources of damage to light bulb wiring is rodents. This is especially common in autumn when squirrels, mice and other rodents are looking for warm places to build nests. They will gnaw on wiring for use in their nests.
Melting: If your wiring harness is not protected by proper routing (wiring is not secured and out of the way), it can come into contact with any number of hot surfaces under the hood. While wires tolerate high ambient temperatures relatively well, they do not tolerate direct heat.
Vibration related wearA: Every part of your car vibrates when the engine is running, and if your wires are not properly secured, it is possible that they will come into contact with other components while the car is running. Over time, this can lead to abrasion - the insulation actually wears down, exposing the inner wire and potentially creating a short circuit.
Accident damage: Another very common cause of bulb wiring damage is a frontal collision. Even seemingly minor accidents can result in hidden damage, including a broken or torn headlight harness.
Broken solder pointsA: While most of your headlight wiring is continuous, there are solder points in a few key locations. These are weak points that can fail over time (heat, vibration, frequent replacement and other factors can cause damage).
As you can see, there are many ways to damage light bulb wiring. Once damage occurs, you will need to have it repaired by a professional mechanic.
