What must build a wiring harness for your new HID system to be correctly controlled by your factory headlight circuit? You can’t expect the ballasts to plug into the sockets that power the halogen bulbs and work correctly or even at all, in addition to ensuring that your car’s outputs are converted for compatibility with your ballasts (and, if necessary, projector solenoids), a harness doubles as a power source for these parts. We’ve included a list of questions to ask yourself to help you choose the best option for your application because wiring is one of the trickier aspects of a headlight upgrade.
1. Does the Car Have a Canbus System?
To check and ensure that all of these systems are functioning properly, the ECU on the car connects with numerous components all around it using the can-bus technology. It is crucial to keep this in mind because difficulties arise if the ECU detects that the resistance across the headlight circuit is different from what it has been designed to accept as normal. There could be anything from a straightforward “lamp out” message on the dashboard to a persistent flicker in the headlights.
The solution is usually as simple as adding a small amount of resistance to the circuit, making the car believe that the original headlight bulbs are still plugged in. Standard relay wiring harnesses that connect to one side of the vehicle won’t work since they leave the second factory output completely unconnected; instead, they will need a whole different wiring harness utilizing both factory outputs. For most European applications, Morimoto solo can-bus harnesses are the recommended solution. Still, the Mopar harness series is advised for most American vehicles with CanBus difficulties.
2. Did the Car Come with a Factory HID?
You probably won’t need any relay harnesses if you’re replacing or upgrading the ballasts on a car with HID headlights. A low beam relay harness is necessary if you’re installing additional hid ballasts to operate in addition to the factory hid, such as when switching to quad projectors. Since you must connect to the -/+ input that powers one of the current ballasts, the input specification on the harness is irrelevant.
3. What is the Actual Type of Halogen Bulb that a Car Uses for Its Low Beam/Main Headlight?
It is where the answer to this query is. It establishes the precise hash required, such as 9006, h4, etc. As a result, you can decide if you want a low beam or bi-xenon harness that matches a particular input. For instance, a 9005 headlight bulb harness will be a common beam model, while H4 is a bi-xenon model.
4. Does the Car Have Daytime Running Lights (DRL)?
Don’t worry if the car’s high beam has a daytime running light because it has no impact. Use a standard relay harness if the vehicle does not have a can-bus system and has a daytime running light on the low beam. You’ll use your DRL instead of the low-beam HID. Suppose a vehicle has a can-bus system and a quiet voltage daytime running light on the low beam. In that case, this creates an issue because the conventional relay harness will cause a lamp-out warning or flickering. The can-bus harnesses won’t be able to supply enough power to the ballasts. The best solution is to turn off the DRL.
5. Are You Doing a Quad Projector Retrofit?
When you had a quad projector conversion, your original headlights were likely configured with a separate low and high beam bulb. In response to the first question above, you most likely selected a low beam harness, such as a 9005, 9006, H7, or H11. You will need two harnesses for this application since each will have two outputs. Finally, the car’s two original low-beam outcomes include results for four ballasts.
You must choose the can-bus harnesses and keep in mind to turn on your low beams every time you drive. If that is not technically or legally possible (for example, if you live in Canada, where all vehicles must have them). By doing so, the headlight circuit will receive full voltage (instead of half) and the power the ballasts require to operate without flickering.