This is one of the most important questions that is confusing many people these days! Many of us while handling our HID kit are confused as to whether or not to opt for using a relay harness. Well, the answer to this important question depends upon a number of other factors, such as the type of application, HID kit installation location, low beam/high beam/fog light use, etc.
Most of the time an HID kit can be plugged directly into the headlight panel socket. However, the results will vary depending upon the type of the wiring in the vehicle and the use of automatic light controls. In the older car models, generally the headlights withdraw power directly from the switch socket.
After the installation of the HID kit, the power consumption will increase, which can burn out the switch over time. This damage can prove to be extremely heavy on your pocket. Especially, if your car was manufactured around 1980, you had better pay close attention to this warning.
But, if your car belongs to the league of the newly manufactured vehicles, you might just escape this disaster. In most of the newly manufactured vehicles, a more dedicated headlight relay based circuit is provided for handling the low beam/high beam/fog lights, etc.
Every car is provided with a light circuit, which is designed around a certain wattage level for the bulb. If the installed HID kit withdraws more power than the reference bulb, the protection fuse most will blow. In some cases, people make use of bigger fuses, but that is really not the safe solution. In doing so, you might just end up burning the wiring harness or even igniting electrical fire. Then, where does the solution lie?
Well, the solution lies in installing an HID based relay harness. Such a system makes use of the light socket in the car for clicking over the relay. This enables the easy flow of power directly from the car battery through the gauge wire, as well as suppling the right fuse size for the operation of the HID ballasts.
If your vehicle has automatic lights or employs low voltage based DRLs, then you should certainly opt for the HID relay harness setup. Most of the relay harness setups cater to the voltage dipping troubles associated with automatic car lights. The operating voltage of the DRLs used in your car will determine the configuration of DRL to be used. If the operating voltage is more than 6.5 volts, a single HID relay harness will work, or else a DRL module has to be used.