Manufacturer Warranty: Windscreens

 

 

I replaced a windscreen for an Audi dealer, however, there was nothing wrong with the glass. I asked what the change was for, and it was pointed out that there was an issue with the automatic rain and light sensor. So why was the windscreen cited as the issue?

In his report, the investigating Audi technician concluded that the sensor was not functioning due to the car having a non-genuine windscreen replacement; the (aftermarket screen in it was made by AGC Automotive). As the car was to be sold whilst still under manufacturer warranty the investigation ended there, and could not be resumed until a genuine, Audi branded glass was in place. I duly obliged. However, shortly into the strip-down I discovered what the cause of the issue really was: a damaged rain sensor. The previous installer had damaged the circuit board inside (there were screwdriver marks in the casing).

The car in question was registered in 2016, so much of its warranty would have still been in place; just as long as any parts replaced were authentic, Audi branded.

Rain Sensor 2

Windscreen Rain Sensor

 

Another similar situation unfolded when a Volkswagen main agent was investigating a sensitivity issue on a rain sensor on a fairly new Golf; the owner said the automatic wipers didn’t seem to react as well as he though they should. The VW technician noted the windscreen, an aftermarket version by Saint Gobain (Sekurit) and quickly surmised that it was the cause of the problem. I went along to give a second opinion.

The first place to look for obvious things that could be wrong with a poorly functioning rain sensor is the rain sensor module. I removed the rear view mirror assembly and immediately saw that the rain sensor was not seated properly in the mounting bracket. A push and a click later, the wiper sensitivity was restored to optimum level. However, VW did tell the Golf owner that if there was an issue with the rain sensor (or windscreen) whilst the car was under manufacturer warranty, it would not be covered owing to the non-genuine windscreen in the car.

Whilst these examples may seem excessive, windscreens can be much more complex than the two highlighted here. With radio antennae; heater elements; GPS hardware; Lane Departure Warning sensors; Autonomous Braking hardware; Head Up Display and more, the windscreen is no longer just a piece of glass shielding the car’s occupants from wind and flies. The best available parts, especially if the car is still under warranty (or the more technology connected to the glass) will always be what the vehicle manufacturer endorses.

 

Minding the ‘A’ Pillar Gap

 

 

 

Is it necessary to remove the ‘A’ pillar trims when replacing a windscreen. For most older, rubber fit windscreens: probably not. However, if you were replacing a bonded windscreen by the book, most definitely: yes.

Windscreen replacement is evolving at a rapid rate. This evolution however, is focusing on a fast fit culture to save time and money. So why is it important to remove the ‘A’ pillar covers, or trims?

Removing the windscreen: the trims are very close to the bond line. When cutting through the cured polyurethane – and whichever cutting method is used – there is risk of damage to the trim, or the trim covering. Some trims may even be touching the polyurethane [PUR] and have adhered to the moulding, or fabric covering.

A pillar trim gap

Too close for comfort

When fitting – or replacing – the windscreen, it is good practice to check for good contact by shining a torch up and down the ‘A’ pillars from inside the car. This is almost impossible to do with the covers in place. Also, if there is any ooze, you can tidy this up to prevent contact with the pillar trims.

'A' pillar trim removed showing proximity to edge

‘A’ pillar trim removed showing proximity to edge

A lot of firms and fitters are using trim protectors to prevent damage to these items, and the advent of fibre cutting wires has further reduced this risk. It does not however mean that the next time the windscreen is replaced any damage will be avoided as there is no emphasis on checking for proper contact; how can you, when it is behind a cover?