We all know that the windows include a codebut almost no one pays a single second of their attention to read what it says there. Among other things, because almost no one knows interpret the number that is written there. However, that code can tell you that a used car has suffered an accident even if the owner or seller tells you otherwise.
At first glance, this code looks like a casual combination of letters, numbers, approval symbols and some other marks strange Most drivers have seen them hundreds of times thinking about something else and never wondering what they mean. And that is what we are going to tell you.
The relevant data
The code is there because car windows must meet a series of safety requirements. approval. For this reason, each moon incorporates information related to the manufacturerhe country where it has been approved and the approximate production date (not the specific day, but the month). It is precisely this last piece of information that can become a very useful tool when you examine a second-hand vehicle.
A Volvo glass produced in March 2024.
The truth is that there is no universal code that use all the brands in the world. Some resort to combinations of numbers and points. Others use stars, small circles or marks distributed around a figure. But the good thing is that all these systems follow the same logic: the main number identifies the year of manufacture in one or two digits. In some years you can put, for example, 23, while in others you can put only 3. It is true that this 3 can mean either 2023 or 2013, but you don’t need much help to know what year the car is from and what year the glass will be. And the complementary points or marks allow us to know the month. Thus, a crystal in which the number 25 (or 5) appears with four dots, asterisks or circles means that the crystal was manufactured in April 2025.
Before the car
Here comes one of the most striking details: the glass is always manufactured before the car. It seems obvious, but many people would expect to find exactly the same year on the vehicle papers and on the windows. Suppliers produce thousands of windows that then travel to assembly lines. For weeks or even months they remain stored until they end up installed in a specific car.
For this reason, a car registered in 2022 can carry perfectly crystals manufactured at the end of 2021. It is even possible to find differences of several months between some moons and others without any reason to worry, because the components They arrive at the factory at different times and they are part of different lots.
In this case, the glass could be from January 2022 or 2012.
The important thing appears when all the crystals are compared to each other. That’s where it begins detective work What you can do before deciding to buy the car. If the side windows, the rear window and the windshield show dates very close to each other (one or two months), everything fits within normality. Because in fact the differences are usually small and consistent with the vehicle manufacturing process.
The situation changes when one of the moons presents a very different date to the rest. At that point you already know that the glass was replaced at some point in the car’s life. At that moment, without confessing that you have seen something strange, you can take the opportunity to ask if the window has been stolen or broken. If they say no, it means that the change has occurred due to an accident he hasn’t told you about.
The windshield is not a concern
The most common case of change affects the windshieldbut alarms should not be raised here because a small chip can end up becoming a crack and force the entire glass to be replaced. In fact, finding a latest windshield The rest of the glass is usually quite normal and, by itself, provides very little information about the vehicle’s history.
March 2025 moon example.
Suspicions increase when differences appear elsewhere. The side windows undergo far fewer replacements over the life of a car, and the same goes for the rear window. When one of these pieces has a date that is clearly different from the others, it is worth investigating a little more.
The reason is simple. A side collision can break one or more windows. A rear impact may require the rear window to be replaced. An accident of some importance can cause the simultaneous replacement of several glasses. Consequently, a date combination that breaks logic of the rest of the vehicle can become a very interesting track.
Professional trick
Although ‘ordinary’ drivers do not know this code, Buying and selling professionals know this resource well. Many use crystals as a first check quickly before examining it thoroughly in the workshop, disassembling anything or connecting a diagnostic machine.
In addition, it is a check that barely requires a minute. Simply walk around the car looking at the corners of all the windows and comparing the codes. The interesting thing is that the newer the car, the easier it is to interpret temporal differences. In models that are twenty or thirty years old, the situation is complicated because windows may have been replaced for very different reasons over decades of use, but with a relatively modern car everything changes.