Why don't ordinary light bulbs in cars become led lights?

Add a decoder, which is a resistor. What model and year is your car? The halogen bulb of the original car is generally 55w, while the led headlights are generally between 20 and 40 W. Due to different powers, the current is different. When the driving computer detects that the current of the newly installed lamp is different from that of the original car, it will prompt whether there is a fault. In fact, there is nothing wrong. Led headlights are bright and energy-saving, which is much better than the halogen bulbs of the original car. If the driving computer prompts, just add a resistor. For example, if the led headlight is 30w, add a resistor of about 25w, which is the same as the original light bulb power. Take the very popular "automobile led headlight a340" as an example. A340 is 40w, just add a resistor 15-20w. In fact, many cars don't need resistors now. Volkswagen, Hyundai, Toyota, Honda, Audi and other more than 90% car led headlights. There is no need to increase the resistance. I used to repair cars, but now I play with cars and like to modify them myself. Know a lot about cars and unconsciously type a lot of words. I hope it will help you a little. Hope to adopt thank you!