What does the rear fog light of a car mean
The rear fog lights of a car are red signal lights installed at the rear of the vehicle, used to enhance the visibility behind the vehicle in low-visibility environments such as rain, fog, and snow. Its luminous intensity is greater than that of ordinary taillights. It uses a red light source to enhance penetration, making it easier for traffic participants behind to spot the vehicle.
Main functions
The rear fog lights automatically turn on in weather conditions with low visibility (such as fog, rain, and snow), penetrating the rain and fog with high-brightness red light to reduce the risk of rear-end collisions. According to Chinese regulations, all motor vehicles must be equipped with fog lights that meet national standards. Vehicles without such installation are not allowed to enter expressways.
Usage rules
The fog lights can only be turned on after the position lights (small lights or large lights) are turned on
Different vehicle models have different switch methods. Common types include knob type, key type, combination switch type, etc. Youdaoplaceholder0
Most countries mandate installation, but there are differences in usage rules (for example, France and Germany require installation but prohibit use when good can be seen)
The rear fog lamp is a safety device for vehicles to enhance visibility in low-visibility environments such as rain, fog, and snow. It usually uses a red light source to increase penetration. Depending on the design differences of the vehicle models, the rear fog lights come in two forms: single-side configuration (more common in European models) and dual-side configuration. Some models can achieve functional expansion through later modifications. Its installation location must comply with the requirements of the "Technical Conditions for the Operation Safety of Motor Vehicles", and be within the range of 35cm to 1 meter above the ground at the rear of the vehicle. When maintaining, the contact assembly of the bumper or wheel arch components needs to be disassembled. Some models support direct replacement without removing the bumper (for the BYD S6 model, only one fixing screw and a clip need to be removed to replace the rear fog lamp assembly).
The common causes and solutions of rear fog lamp failure are as follows :
Youdaoplaceholder0 Core fault cause and troubleshooting steps
Youdaoplaceholder0 The bulb is broken .
Youdaoplaceholder0 inspection method : Observe whether the bulb is black or cracked. If the appearance is normal, the resistance value needs to be further tested (normal resistance is usually between 20 and 100 ohms).
Youdaoplaceholder0 solution : Replace with a new bulb of the same specification (for example, the Toyota Corolla uses a wedge-shaped seat 21W bulb).
Youdaoplaceholder0 circuit or fuse problem .
Youdaoplaceholder0 check steps :
Confirm whether the fuse has blown (the corresponding position is usually in the fuse box in the engine compartment or the driver's cabin).
Use a multimeter to test the continuity of the circuit and check if there is a short circuit, open circuit or poor contact in the line.
Youdaoplaceholder0 solution : Replace the fuse with the corresponding specification (for example, for Toyota models, a fuse with the rated current should be matched).
Youdaoplaceholder0 switch or relay failure .
Youdaoplaceholder0 detection method : If the bulb and fuse are normal, it is necessary to check whether the fog lamp switch has poor contact or is damaged.
Youdaoplaceholder0 solution : Replace the switch or relay (for some models, the fault code needs to be read through OBD to locate the problem).
Youdaoplaceholder0 Special circumstances and modification effects
Youdaoplaceholder0 Circuit conflict caused by modifying the reversing camera : Some car owners mistakenly connected the circuit when installing the reversing camera, resulting in abnormal fog light control. For example:
The power cord of the reversing camera was mistakenly connected to the fog lamp control terminal (such as the black/red line of the blue plug). The circuit needs to be reorganized and connected correctly.
Youdaoplaceholder0 Design defect : For some models, due to circuit design issues (such as power supply logic errors in dual-voltage models), the fog lights on one side may malfunction. The original factory module needs to be replaced for repair.
Youdaoplaceholder0 Daily maintenance suggestions
Youdaoplaceholder0 Regular check : Use the phone flash to test the dark light function (simulate the lighting test) every quarter to avoid insufficient brightness caused by light attenuation.
Youdaoplaceholder0 Professional maintenance : If it involves circuit design or module replacement, it is recommended to handle it at a 4S store or a professional maintenance point to avoid causing more problems by self-operation.
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