The coil wire connects the coil to the distributor. The distributor is connected to the spark plug in a vehicle’s ignition. These coils are used to convert the power of the vehicles’ 12volt battery in to a much higher current, and the current is then used to ignite the fuel and air combination using a spark from the spark plug. It is the job of the coil wire to transmit the larger current from each coil to the distributor and the distributor sends this power to the spark plug to create the spark and allow the vehicle to operate.
If a coil wire is damaged this could cause timing issues with the spark plugs, meaning the spark is created at the wrong time and does not ignite the fuel air combination. Just one faulty coil wire can cause the engine to misfire so it is important to make sure they are well maintained. With any engine problems you are likely to get an error message on your dashboard suggesting an engine check. If this occurs, be sure to check the coil wires and buy immediate replacements if any of these appear worn or damaged.