Why do you have to pull the wiring harness from the battery when changing the fuse?
Provide sufficient power: For some modified headlamps, such as xenon lamps and high-power LED lamps, their power is higher than that of the original vehicle’s headlights. The original vehicle’s wiring harness is unable to supply sufficient current. The wire harness from the battery can ensure that the headlamps receive stable and sufficient power, enabling them to work properly.
Protecting the original vehicle circuit: If the lights are directly connected to the original vehicle wiring harness, the large current may cause the original vehicle circuits to overheat, overload, and even be eroded, increasing the risks of short circuits and spontaneous combustion. By pulling the wire from the battery and equipping independent fuses and relays, the current load can be transferred to the new wiring harness, protecting the original vehicle circuits.
Adapting to control requirements: Modern cars mostly use CAN lines or LIN lines to control the lights, and the output voltage is not the traditional 12 volts, so they cannot be directly powered by the modified lights. By pulling the wire from the battery and cooperating with the corresponding control module, it can better adapt to the control requirements of the modified lights, achieving normal switching, dimming and other functions.
In some cases, the lamp can be replaced without adding wiring harnesses:
Original vehicle line support: If the original vehicle’s headlights are halogen lamps and there is room for upgrade, or if the original vehicle’s wiring has a thick diameter and strong load-bearing capacity, and if you want to install small-power LED lamps with low power demand that do not increase the load on the original vehicle’s wiring, you can do so without adding a wiring harness. You can directly utilize the original vehicle’s wiring.
Special design products: Some plug-and-play modified lamps have been optimized in design and have built-in circuits, enabling them to work without increasing the burden on the original vehicle’s wiring. For example, some LED bulbs with built-in decoding functions and low power consumption do not require additional wiring.