The function of the split rear lights of a car
The core function of the split rear lights of a car is to separate the lighting, warning functions and aesthetic design, ensuring they do not interfere with each other, and reducing manufacturing and maintenance costs.
The functional division is clearer: The common practice is that the upper part is responsible for the shape and width indication, while the lower part focuses on the brake lights, turn signals, and reverse lights. For example, the split rear lights of the new Audi A6L, the upper part is delicate and responsible for "beauty", while the lower part is responsible for "functionality". It lights up when needed and flashes when required, and there is no conflict between appearance and practicality.
Lower cost and simpler structure: Split rear lights are mostly independent light groups, with small part sizes and simple structures. The manufacturing process requirements are relatively low, making them more friendly to mid-range and low-end models. Repairing or replacing a single side or single light after a collision is also more cost-effective.
No necessarily lower recognition: Well-designed ones still have high recognition. For example, models like Honda Odyssey, Guangqi E9, and Volvo EM90, when the rear lights are illuminated, the outline is clear, and they are easily recognizable by the following vehicle at night.
Support for more intelligent lighting interaction: The OLED split rear lights of Audi A6L have each light unit independently controlled. During emergency braking or automatic parking, they can display triangular light symbols, and through car-to-x vehicle-to-infrastructure communication, they can actively warn the following vehicle. This is a major advancement in functionality of the split design.
How to choose between split and continuous rear lights
The advantage of continuous rear lights is that a single light strip can outline the vehicle's shape, making it easier for the following vehicle to notice in rainy or foggy weather, and visually more complete and unified. However, the components are large, the structure is complex, and the manufacturing cost is higher. The split design, on the other hand, is superior in practicality, economy, and ease of maintenance. There is no absolute superiority or inferiority; it is more a difference in design orientation and cost positioning.
The troubleshooting process for split rear lights is similar to that of ordinary rear lights. The core is to first determine whether it is one side not lighting up, part not lighting up, or always lighting up, and then follow the sequence of "bulb → fuse → wiring → switch/module" to check. The fault point is usually still these types.
Common fault causes
Bulb burnout: The most common. The filament breaks or the bulb turns black. Replace the same specification new bulb. The split rear lights have independent bulbs for each segment. If one segment does not light up, it is likely to be a problem with the corresponding bulb.
Fuse melting: The fuse in the corresponding circuit burns out, causing the rear lights to lose power. Check the user manual to find the location of the fuse box, replace the same specification fuse, and do not randomly replace with a larger ampere rating.
Poor wiring and contact issues: Loose plugs, oxidation, corrosion, or damaged wiring harnesses can cause current not to flow. Clean the rust, reinsert the plug tightly, and pay special attention to the aging of the wiring harness in old vehicles.
Switch or control module failure: If the brake light switch is broken, the brake light will not light up or always light up; if the electronic control module is faulty, it may also cause abnormal operation of the rear lights. Professional diagnostic equipment is required for detection.
Step-by-step troubleshooting process
First, observe the symptoms: Determine whether it is one side not lighting up or both sides not lighting up. One-sided non-lighting is mostly related to the bulb or contact, while both sides not lighting up is more likely to be a problem with the fuse, switch, or wiring.
Check the bulb: Turn off the power, open the trunk to find the rear light assembly, remove the bulb to check the filament and blackening condition. If it is broken, replace it with the same model.
Check the fuse: Compare the manual to find the fuse corresponding to the rear lights, and check if it has melted.
Check the wiring: Check if the wiring harness plugs are loose, oxidized, corroded, or damaged. Clean and reinsert tightly.
Check the switch/module: Test the brake light by stepping on the brake pedal. If it does not light up, it may be a fault with the brake light switch; if all of the above are normal, use a diagnostic computer to detect the control module.
If the split rear lights are constantly on, don't delay. It will consume the battery and may affect the following vehicle's judgment. If you can't troubleshoot it yourself, go to the repair shop as soon as possible. Safety first.
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