I get asked this question a lot. I will always answer this question with another question that leads into a conversation. I am going to try get all this information out of my head and onto this page. I’ll try not to bore you with math or super detailed information. I just want to cover the basics, so here we go.
First things first, What is the application? What location are you installing the HIDs? Low Beams? High Beams? Fog lights? Replacing a stock DRL? (Daytime Running Light)
In most cases you can just plug the HID Ballast directly into your car or trucks headlight socket. Depending on how your car or truck is wired and if it is equipped automatic light controls you can get different results. I have heard the idea that the headlights pull power directly through the headlight switch itself. The added initial power consumption of HIDs will then, over time, burn out your switch which is expensive to replace. If your car was manufactured pre-1980 you may need to heed this warning. But if you own a newer car it most likely has a dedicated, fused headlight circuit starting at a relay. This also applies to your High Beams and Fog Lights.
Note before that I stated a “Fused Headlight Circuit“. This is why we offer an HID Relay Harness. What amperage is the fuse rated for your light circuit? 10 Amp? 15 Amp? 20 Amp? Every vehicle manufacturer designs the light circuit around a specified wattage of the bulb being powered. If the HIDs draw more power than that bulb you will most likely blow the fuse that is protecting the circuit. Some guys just throw the next size bigger fuse in and it works, is that safe? NO, not really. Consider that the gauge of the wiring used is calculated for the draw of the Halogen bulb you just replaced and for the original size fuse that kept blowing. IF you choose to just up the size of the fuse you may end up with a melted wiring harness! Or worse yet, an electrical FIRE! Instead you should install an HID Relay Harness. It uses the cars light socket to click over a relay and this allows power to be pulled directly from the battery via sufficient gauge wire and a proper size fuse for HID Ballasts to operate.
Does your car or truck have automatic lights? Does your car use this circuit as a low voltage DRL? If you answered YES to either of these questions I would recommend using an HID Relay Harness.
The “Auto Lights” feature on cars will turn your lights on as soon as you turn the key to the Ignition Position. When you crank the engine over all accessories including your lights will turn off. After the engine starts and you let the key go back to the Ignition position the lights will come back on. This will cause misfires from the voltage dipping when it cuts out. In most cases the Relay Harness will correct this problem.
The “DRL” poses more than one problem. Depending on the operating voltage of the DRL will depict if you need more than just an HID Relay Harness. If you can test the voltage with a test meter and it shows a voltage of 6.5 Volts or greater you can use just the HID Relay Harness. If the voltage is less than 6.5 Volts you can use one of our DRL_MODULES. The DRL_ MODULE is my best friend when it comes to finding a solution for low voltage issues. It is essentially a power booster. It will take as little as 3 Volts and bump it all the way up to 14 Volts! You can install this between the light socket and the input of the Relay Harness and voilà! Now you have enough voltage to click over your HID Relay Harness. A properly installed HID Relay Harness will fix most problems before you ever experience them. It’s a small price and adds a little extra install time, but I like a little peace of mind.
Thanks for reading, feel free to leave a comment or ask a question. You can contact me via email directly here too: firstname.lastname@example.org.