Installing new adhesive pad for rain sensor — VW

Installing new adhesive pad for rain sensor
Applies to Valeo rain sensors.
The rain sensor is connected air-tight to the windscreen, within its retaining ring, by a transparent adhesive pad (Silgel coupling pad). This adhesive pad prevents foreign objects penetrating the gap between the rain sensor optical module and the inside of the windscreen and thereby disturbing the function of the rain sensor.
In cases of repair, if the rain sensor is removed from its retaining ring the adhesive pad must be assumed to be damaged and therefore replaced. The replacement parts can be obtained individually
parts catalogue
.
Note
The new adhesive pad must be fitted using extreme care concerning cleanliness and must not be touched with e.g. bare fingers or tools. Otherwise the adhesive pad may become contaminated causing the rain sensor to malfunction.
Preparing windscreen:
The rain sensor contact surface within the retaining ring on the windscreen must be free of all forms of soiling such as dust and grease. Thoroughly clean the contact surface with isopropanol (isopropyl alcohol).
Preparing rain sensor:
Use your fingers to pull the damaged adhesive pad off the optic module of the rain sensor.
Caution
The optic module of the rain sensor can be damaged!
Do not use tools to pull off the damaged adhesive pad.
Only use your fingers to carefully pull of the damaged adhesive pad.
Ensure the damaged adhesive pad is completely removed from the optic module of the rain sensor.
Then, use isopropanol to remove fingerprints, dust and grease from contact surface of optic module.
Bonding a new adhesive pad to rain sensor:
Pull yellow protective film off new adhesive pad.
Applying pressure, roll new adhesive pad with red carrier foil onto rain sensor in such a way that it is centred on optic module.
Note
A rolling motion is required to prevent air bubbles between the adhesive pad and the optic module of the rain sensor.
Firmly press on red carrier foil to press the new adhesive pad onto the contact surface of the optic module.
Carefully pull red carrier foil off adhesive pad on optic module.
Note
In order to pull off the red carrier foil, look for a point on the circumference of the carrier foil which can be released easily from the adhesive pad.
Make sure that the adhesive pad is not damaged by the action of pulling off the carrier foil and that the pad has not come away from the contact surface of the optic module.
Install rain sensor immediately.
Installing rain sensor:
Moisten the surface of the new adhesive pad completely with a thin film of isopropanol.
Note
We recommend using a pipette to moisten the surface of the adhesive pad with isopropanol.
Only moisten the surface of the adhesive pad with a thin film of isopropanol.
Caution
Danger of fire!
Isopropanol is highly inflammable.
Smoking and naked lights are prohibited during the installation procedure.
Immediately install the rain sensor into its retaining ring on the windscreen after moistening the adhesive pad to prevent contamination on the adhesive pad. To prevent bubbles forming between the adhesive pad and the inside of the windscreen when bonding the rain sensor in, the rain sensor must be inserted into the retaining ring in such a way that only one point of its circumference initially comes into contact with the windscreen.
Insert rain sensor with moistened adhesive pad into securing ring on windscreen so that only the outer edge opposite the connection line initially comes into contact.
Now lightly press rain sensor completely into securing ring, start at the edge making contact and move towards the connector wiring.
Note
At the stage of the bonding process it is possible to make slight corrections to the position of the rain sensor in the retaining ring.
When correcting position, ensure that no air bubbles are formed between the adhesive pad and the inside of the windscreen.
If an air bubble is created, increase the pressure when pressing the rain sensor into the securing ring.
Maintain light pressure on the rain sensor and wait for approx. 3 minutes until the isopropanol between the adhesive pad and the windscreen has evaporated completely.
Install cable ducts
1
and
2
.
Check adhesive side of rain sensor for air bubbles.
Air bubbles between the adhesive pad and the inside of the windscreen are not permitted.
Remainder of installation is carried out in reverse order of removal.