That yellow light on your wing mirror is usually a Blind Spot Warning (BSW) or Lane Change Assist indicator, using radar sensors to alert you to vehicles in your blind spot, helping prevent collisions when changing lanes, and it can also signal system warnings or active features like pedestrian detection, varying by car model.
When a car is detected, a yellow or red indicator will light up in the side mirror or on the window frame. Some systems also provide a warning sound. BSW helps you to avoid crashes that occur in blind spot areas. They are most effective when your car is passing, being passed, or preparing to make a lane change.
The blind spot information feature helps increase your awareness of vehicles in or approaching your blind spots. A light appears in the wing mirror when a vehicle is detected. Blind spot alerts can increase your awareness of vehicles to the side of your car, which can help you avoid performing dangerous lane changes.
To tell if a mirror is two-way using your finger (the "fingernail test"), press your fingertip to the glass; if there's a gap between your finger and its reflection, it's a normal mirror, but if your finger and its reflection appear to touch, it's likely a two-way mirror (or first-surface mirror) because the reflective coating is on the front surface. This works because standard mirrors have the coating behind glass, creating a tiny space, while two-way mirrors have the coating on the front, so the reflection appears right at your fingertip.
Blind spot mirrors and monitors
These are sensors located on the car which notify the driver via an audible or visual signal (normally a light on the wing mirror) when a vehicle is in their blind spot.
Check If There's a Hidden Camera behind the Mirror
Put your fingernail on the mirror. Observe the gap between your finger and the mirror. See if there's a gap between your finger and the image, it's a real mirror. If your finger and the image touch tip to tip, there might be a hidden spy camera in the mirror.
Blind-spot warning (BSW)
It then warns the driver that another vehicle is in a position that could be dangerous if they decide to change lanes. The warning is usually a flashing light, perhaps in the wing mirror, or a loud beep.
Fingernail drug testing is known for its high level of accuracy, provided the test is administered and processed by an accredited lab such as Smart Labs Now . Accredited testing laboratories must follow strict international quality standards, ensuring their processes meet rigorous guidelines.
To do this test, simply pull out a standard mirror from your purse or pocket. Put it up next to the mirror and check to see if the tint looks the same as your mirror. If it appears darker, it is likely a two way mirror.
In a car, a triangle with an exclamation mark (⚠) is the Master Warning Light, indicating a general or unspecified fault that needs attention, often appearing with another, more specific light or message to pinpoint the problem, like issues with brakes, traction control, or other systems, so you should check your owner's manual and get it serviced soon.
If your fingers touch in a mirror (no gap between your fingertip and its reflection), it often means it's a two-way mirror, not a standard mirror, because the reflective coating is on the front surface, allowing light to pass through to a darker area behind. In a normal mirror, a tiny gap exists because the reflection comes from a silvered backing behind the glass, so the image is slightly behind the actual surface. This "fingernail test" is a common way to check for secret mirrors in places like hotel bathrooms or changing rooms, though it's not foolproof.
Yellow (sometimes orange) dashboard lights usually mean something needs to be repaired or serviced soon and to operate with caution. If this lamp illuminates while the engine is running, a potential issue with the emission system is indicated.
The Master Warning Light (a yellow/orange triangle with an exclamation mark) is a general alert in your car's dashboard indicating one or more of your vehicle's advanced systems have detected a fault, requiring you to check the driver's display for specific messages like low tire pressure, a door ajar, or issues with stability control, and seek professional help if needed.
A Blind Spot Information System (BLIS) can help you change lanes more safely. That's because RADAR sensors scan the blind spots on either side of your vehicle. And if they detect a vehicle you can't see, an orange light that's clearly displayed in the corresponding side door mirror illuminates to warn you.
To tell if a mirror is two-way using your finger (the "fingernail test"), press your fingertip to the glass; if there's a gap between your finger and its reflection, it's a normal mirror, but if your finger and its reflection appear to touch, it's likely a two-way mirror (or first-surface mirror) because the reflective coating is on the front surface. This works because standard mirrors have the coating behind glass, creating a tiny space, while two-way mirrors have the coating on the front, so the reflection appears right at your fingertip.
Koilonychia is when your nails have an indented shape, like a spoon. Often, spoon nails are a sign of iron deficiency. You're also more likely to have spoon nails if you have an autoimmune disease, such as lupus, or poor blood flow to your hands or feet.
Fingernails are four times thicker than the typical strand of hair and often capture more substance than hair can. Drug and alcohol biomarkers may be detectable in fingernails for up to approximately 3-6 months. Environmental exposure to illicit substances can be detected immediately in nail samples.
You can detect a hidden camera by using a flashlight, smartphone camera, RF detector, or Wi-Fi scanner app. Look for reflections from lenses, suspicious objects facing private areas, or unknown devices connected to local networks. Each method offers a different layer of detection.
Puddle lights are a feature on some vehicles designed to improve safety and convenience. These are small lights installed on the underside of car doors or side mirrors. When the door is opened or the vehicle is unlocked (often remotely), these lights illuminate the ground around the doors.
NCT and MOT Considerations
In the event of a failed MOT or NCT due to a broken mirror glass, or a damaged wing mirror, drivers will need to rectify the issue with the wing mirror and have their vehicle retested.