Why Your Windscreen Markings Matter for Safety and Ordering
Imagine arriving at work with a chipped windscreen and your fleet manager asking, “Can you get it fixed today without grounding the vehicle?” The tiny etched code in the corner—known as the glass bug—controls whether we can order and fit the exact replacement that morning. This guide is for fleet managers, technicians and drivers in the UK who need a fast, accurate windscreen match that keeps ADAS, heaters and MOT compliance intact.
In our experience, getting the bug details right is the single fastest way to avoid delays and extra cost. Read on to learn where to find the key markings, which features change the part you need, what photos to send for a same‑day match, and the calibration and compliance steps after replacement.
Where to Find the Markings and VIN on Your Vehicle
The bug typically sits in the lower corner of the windscreen—either driver or passenger side. The VIN is often at the base of the screen on the driver’s side, and also appears on the V5C and driver’s door jamb. A common issue we see is customers sending a wide photo but missing the close‑up bug shot, which slows quotes.
Photo tips for a fast quote: take a clear, straight‑on close‑up of the bug, a shot of the mirror/sensor area, and a wide exterior shot of the whole screen. These let us confirm brackets, sensor pads and tint variants so we can order the exact part first time.
E‑Marks Explained: Approvals and Compliance
The E‑mark is a circle E plus a number (for example E1 or E9) showing the country of approval; “43R” denotes European approval for laminated automotive glass. UK windscreens are laminated for occupant safety; side and rear glass may be tempered. You may also see DOT/AS or BS codes.
When you contact Fleet Motorglass, send the full bug text, E‑number and clear photos. This confirms the specification we must supply for MOT compliance and ensures any ADAS interfaces are correctly matched.
This image was generated with AI and may not always represent the product or service exactly.
Tint Codes and Sunband Shades: What They Mean and What’s Legal
Visible Light Transmission (VLT) tells you how much light the glass lets through. Factory sunbands and tints are type‑approved; aftermarket film on the windscreen usually isn’t legal. UK law requires the windscreen to allow at least 75% light through.
If you need detail on legal limits or approved factory tints, see our window tinting rules and regulations page for full guidance: window tinting rules.
Feature Icons That Change The Glass You Need
Feature icons and printed notes on the glass indicate heated elements, acoustic layers, antenna lines, HUD zones and sensor pads. Heated screens show fine wires or a heater icon; acoustic glass may be labelled “Acoustic”. These details change the part number and electrical connectors we must match.
A common issue we see is mistaking an aerial line for a decorative mark—sending clear photos of the mirror area removes guesswork. For a deeper technical overview, read our heated, acoustic and HUD windscreen guide: heated, acoustic and HUD guide.
ADAS Cameras and Calibration After Windscreen Replacement
ADAS systems rely on cameras mounted to or against the windscreen; glass thickness, coatings and bracket position affect line‑of‑sight. The wrong screen can distort readings and compromise safety. We source the correct OEM or approved equivalent part for your camera system.
After replacement you will usually need static and/or dynamic ADAS calibration to restore accuracy and meet insurer requirements. Fleet Motorglass offers mobile calibration across Beds, Bucks and Herts—details here: ADAS calibration after windscreen replacement.
OEM Logos, Model Codes and Date Dots: Matching Parts Exactly
Look for brand names such as Pilkington, Saint‑Gobain or Fuyao and model strings near the bug. Date dots and batch codes help verify the variant. We cross‑check your bug text, VIN and sensor photos to order the precise glass—tint, sunband, brackets and tech included.
If you’re concerned about aftermarket quality versus original equipment, we discuss options and supply approved alternatives where appropriate. Read more about replacement quality on our site: is a replacement windscreen as good as the original.
This image was generated with AI and may not always represent the product or service exactly.
What Most People Get Wrong
Many assume any windscreen with the correct shape will work. In practice, missing a tiny sensor pad, sunband shade or heater connector can turn a fast replacement into a two‑visit job. Send the bug and mirror area photos first—this saves time and cost.
Quick Checklist
- Close‑up photo of the bug (legible text and numbers)
- Photo of mirror/camera/sensor area (from outside)
- Wide shot of the whole windscreen
- Reg/VIN, vehicle make/model/trim and year
When This Doesn’t Apply
If your damage is cosmetic, off the glazing area and away from sensors, you may not need a full replacement or ADAS calibration. Also, older vehicles without camera/radar systems rarely need calibration—confirm with photos and VIN.
Repair or Replace? What Your Markings Don’t Tell You
Markings identify the correct replacement but not whether the screen can be repaired. Small chips outside the driver’s “A‑zone” are often repairable. Cracks that reach the A‑zone, multiple impact sites or edge breaks usually require replacement to pass an MOT and retain structural integrity.
Act quickly: moisture and vibration turn small chips into long cracks. Early repair is cheaper, keeps the original seal and avoids unnecessary replacement.
Local, Mobile and Fast: Service Coverage and Booking
Fleet Motorglass operates mobile teams across Bedfordshire, Buckinghamshire and Hertfordshire, including Luton, Milton Keynes, St Albans, Watford, Bedford and Aylesbury. Most jobs are same‑day or next‑day depending on stock and weather.
We manage insurer requirements, provide ATA‑qualified technicians and complete ADAS calibration onsite where needed. For replacements and full service details see our windscreen replacements and contact pages: windscreen replacements and contact us.
FAQs
How do I decide between repair and replacement?
Send photos and VIN. We assess chip size, location and any edge involvement. If the damage is in the A‑zone or there are cracks, we’ll recommend replacement; small peripheral chips are often repaired.
What photos give you a reliable, same‑day quote?
A legible close‑up of the bug, a clear shot of the mirror/camera area and a wide exterior image of the whole windscreen—these three images let us confirm part, brackets and any sensors.
Will ADAS calibration add a lot of cost or downtime?
Calibration adds time but not always substantial cost. Static calibrations are quick at location; dynamic calibrations need a short road test. We confirm requirements with your VIN and sensor photos before booking.
Can I use insurers for a mobile replacement and calibration?
Yes—most insurers accept mobile replacement and on‑site calibration. We handle insurer paperwork and explain any excess or policy implications before we start work.
Is an approved aftermarket glass safe for my fleet?
Approved aftermarket glass with the correct E‑mark/43R and matching features is MOT‑compliant and safe when fitted by qualified technicians. We only fit compliant parts and complete required calibrations.