
The Vios has one rear fog light. Here is an introduction to car lighting: Function of fog lights: Fog lights are installed at the front and rear of the vehicle to illuminate the road and alert vehicles in front and behind to maintain distance during rainy or foggy conditions. However, fog lights should not be used when driving at night without fog, as the front fog lights lack a glare shield and the rear fog light bulbs have high wattage. This can create dazzling brightness for oncoming drivers and those following behind, further compromising driving safety. Installation standards for fog lights: The emitted light must not directly or indirectly cause discomfort to the driver through the rearview mirror or other vehicle reflections. The light direction should remain forward and not change with the steering angle, and the emitted light should not cause glare or discomfort to oncoming drivers or other road users.

As an automotive enthusiast who frequently interacts with various car models, I can tell you that the Vios' rear fog light typically only illuminates on one side, usually on the driver's side rear. This is actually not a malfunction but a design specification aimed at avoiding confusion with brake lights in inclement weather and enhancing safety. If you suspect an issue, try activating the rear fog light switch during foggy conditions and crouch down to verify the illumination. Many car owners mistakenly assume both should light up, but under standard configuration, only the left one illuminates—the right side may be a reflector or reserved position but remains unlit. For further verification, you can refer to your user manual or visit a 4S shop to check if the wiring and switch are functioning properly. This design is quite common globally, primarily due to regulations requiring simplified identification for quicker recognition by other drivers. Personally, I find this design quite reasonable—it's both eco-friendly and energy-efficient.

From a safe driving perspective, I've looked into similar issues. The Vios typically has only one rear fog light illuminated, with the specific side depending on the model year, but it's commonly the left side alone. This is primarily for safety considerations: in dense fog, having both lights on could cause confusion with tail lights or brake lights, increasing accident risks. I recommend owners test this practically: sit in the driver's seat, activate the rear fog light switch, then step out to observe. You'll notice it's not symmetrical like the front fog lights, which is completely normal. If neither light illuminates or there's abnormal flashing, it might indicate a burnt bulb, poor wiring contact, or fuse issues requiring prompt repair. Actually, many compact cars adopt this design - it's cost-effective yet efficient. Maintaining proper fog light function is crucial for nighttime driving, so ensure your Vios' lighting system gets regular checks.

As a Vios owner, I noticed shortly after purchasing the car that the rear fog light usually only illuminates on one side—the left one, while the right remains off. Initially, I thought it was broken, but after checking the manual and consulting friends, I found this is the manufacturer's default setting. If you're unsure about your own car, a simple test can be done: start the engine at dusk, press the rear fog light button, and walk to the rear to see which light is on. Don’t mistake this for a defect—it helps distinguish from other vehicle lights and reduces driving distractions. Personally, I think since it’s the standard, there’s no need to dwell on it. Regular maintenance is key, like cleaning around the bulb to prevent dirt obstruction, ensuring safety comes first.


