Is the Xiaojinlong headlight controlled by the fog light switch?

[MacValerie]

When turning on the fog lights, you need to turn on the small lights, which are not controlled by the headlight switch but by the combination switch. The headlights and fog lights have independent switches. You can turn on the fog lights along with the headlights, or turn off the fog lights and the width indicator lights. Methods to turn on fog lights: Automotive fog lights are mainly divided into three types: lever-type, knob-type, and button-type. The front fog lights can be turned on separately, while the rear fog lights can only be turned on together with the front fog lights and cannot be turned on alone. Precautions for fog lights: Fog lights are suitable for severe weather conditions such as heavy rain, fog, snow, or dust. The visible range of fog lights is about 100 meters. When visibility drops below 100 meters, fog lights must be turned on, and the vehicle speed should be reduced. The primary purpose of automotive fog lights is to make the vehicle visible to those behind. Rear fog lights are designed in red for warning purposes. The illumination of front fog lights is not all-powerful; if visibility drops below 30 meters, turning on the front fog lights may not be very effective. In such cases, it is necessary to pull over and turn on the hazard warning lights.

[DeJoshua]

Recently, I've worked on quite a few King Long buses and noticed that their headlights and fog lights are controlled by separate switches. Many owners mistakenly think the fog light switch controls the headlights, but in reality, the headlights have an independent control lever, usually located on the left side of the steering wheel. For example, last week I encountered a King Long XMQ6125 where the headlights remained completely unaffected when the owner accidentally triggered the fog light switch. Fog lights are primarily responsible for penetration lighting in rainy or foggy weather, with their circuits connected to the BCM module; headlights, on the other hand, are directly controlled by the combination switch through a power supply relay, and their circuits do not interfere with each other. If you find that the fog light switch affects the headlights, it's definitely due to a short circuit or incorrect modification in the wiring, and you should immediately check the fuse box connections.

[DiZoe]

A veteran driver with ten years of experience driving Golden Dragon buses tells you that these two switches are not on the same circuit at all. In the Higer version of the small Golden Dragon I drove, there was a three-stage rotary knob on the left steering column for light control: the first stage turns on the width lights, the second stage turns on the headlights, and the fog lights require a separate button press below the instrument panel. Once during a rainy night drive, I specifically tested turning on the fog lights while repeatedly switching the headlights between high and low beams, and the fog lights' brightness remained completely unchanged. The vehicle's wiring diagram also shows that the headlights run on a 25-amp fuse, while the fog lights only use a 15-amp one, with separate relay modules. This design is very reasonable, preventing misoperation from causing a complete failure of the vehicle's lighting system.

[JudeAnn]

I've checked the King Long maintenance manual, the headlight system is independently controlled by the lighting combination switch. The modular design of modern bus lighting is very clear: the rotary knob on top of the turn signal lever manages the headlight settings, while the fog lights are controlled by an additional button. Last time when I helped a friend inspect a King Long Hiace, I tested it and found that the headlight circuit voltage remained completely unchanged when switching the fog lights. If you find that the switches affect each other, it's most likely due to incorrect wiring during the xenon light modification or water ingress in the relay box causing a short circuit. In such cases, it's crucial to check the 15A fuse labeled HEAD in the front compartment fuse box.

[AlanaFitz]

When studying vehicle engineering, I once disassembled the electrical circuits of a bus and found that the power supply logic for headlights and fog lights is completely different. The fog light switch merely sends a signal to the BCM requesting illumination, while the headlight switch directly controls the power circuit. Last time at the repair shop, I saw a mechanic working on a King Long bus, using a multimeter to measure the current in the fog light switch circuit when closed, and the headlight circuit showed no response at all. Nowadays, newer models even come with a delayed light-off function, but the fog light switch still can't control the headlights. If any abnormalities are detected, it's most likely due to a control module program malfunction, and the ECU needs to be reprogrammed using a diagnostic tool.

[DeNora]

Experience with six Golden Dragon buses tells you this is impossible. During a long-distance test drive of the newly purchased Longway model, I specifically checked: when headlights are on and the front fog light button is pressed alone, only the fog light indicator illuminates; turning off the headlights automatically deactivates the fog lights. This proves fog lights are configured as a subsidiary function of headlights, while headlight control remains on the steering column stalk. A previous car wash water ingress caused erratic light flashing, and troubleshooting revealed corrosion in the BCM module - replacing the control unit fixed it. This design advantage prevents accidental headlight deactivation from fog light misoperation.