Q: How Does a Car's Light Bulb Wiring Get Damaged?

There are many factors to consider when dealing with damaged light bulb wiring both physical and heat related causes can be a concern. The location where the bulb is installed or the actual routing of the wiring to the bulb can play a part in resultant damage. If the bulb is a taillight in the trunk for instance it can put the wiring at risk from damage by objects that are either placed or tossed into the trunk or perhaps shift as the vehicle travels down the road. Another factor to consider is heat.

The types of problems that generally occur are pinching or scuffing of the insulation around the wires which can lead to a short circuit and cause a fuse to open.This is due to the fact that when the wires become grounded they draw excess current (amperage) which will heat the circuit and cause the fuse to open. Most people generally call this a blown fuse. However, the actual fact is that the fuse melts or pops open to protect the circuit from further damage. If the wrong bulb is used or the socket that the bulb is in gets overheated from the bulb or an electrical condition known as resistance due to corrosion then the excess heat created can cause the wiring to melt or become damaged near the point of excess heat.

The socket itself can also melt and result in damage to the wires in the connector itself. The connector is the plastic housing that holds the wires and the socket is where the wires meet the actual contact connections on the bulbs themselves. Sometimes wires are damaged by someone who tries to improperly install an add on accessory or additional lights to a particular circuit.

Wiring can also be damaged if the harness containing the wires is pulled to gain access to a connector instead of releasing it from its secure mount first. If the vehicle was in a prior accident, it may have damaged/changed the routing of the wiring. If you check the wiring run in your vehicle, it is safely packed in a conduit wrap and secured by fasteners of varying types to insure it does not contact a sharp body surface, body pinch point, or hot objects like your exhaust system. These fasteners which secure the harness may degrade or break over time and cause wiring to fall and contact hot or sharp surfaces. Proper adherence to fuse type and amperage are critical when protecting the wiring in your car.