Lighting - Water In Fog Lamps
94 08 382018578/2
November 14, 2008.
Supersedes Technical Service Bulletin Group 94 number 08-15 dated September 18, 2008 for reasons listed below.
Affected Vehicles
94 Fog lamps full of water after driving through water
Condition
Water gets into the fog light after driving through deep water.
Technical Background
Headlights are designed to be open, breathing systems due to the high temperatures generated by the lamps when they are switched on.
As part of the air flow in the headlight, it is possible for damp air to enter the headlight (for example, on foggy days or when driving in the rain).
To achieve a suitable defogging process, there are two vents in a fog light. They are designed in such a way that one of them has slight over-pressure and the other slight under-pressure while travelling. This achieves air circulation within the headlight, accelerating the drying out process of a fogged-up headlight while travelling. Switching on the light will also speed the process up.
When driving through deep water, water may enter into the fog lights through the vents.
There are special fog lights for these customers.
These fog lights only have one vent to provide pressure compensation when using the fog lights. On the vent a Nitto element is installed with a water-repellent membrane that prevents water from entering. Air, however is able to get to the headlight.
If humidity gets into the headlights (e.g. when changing a light bulb), they can no longer be defogged by the missing ventilation system. The defogging conditions are impaired.
Production Solution
N/A
Service
If a problem is reported and a considerable amount of condensation is found in the fog light or if there is widespread corrosion of the reflectors in the fog light (see image), find out from the customer if they drove the vehicle through deep water.
- If the customer has not driven the vehicle through deep water, proceed according to TSB 2012749 Exterior lights, moisture accumulation.
Tip: Installing a set of special fog lights will not solve the problem because the defogging process used by standard fog lights is superior.
- If the customer intends to continue to drive through the fording depth approved by Audi AG (see user manual), then both fog lights should be replaced.
Warranty
When procedure applies to vehicles under warranty, use the table.
All warranty claims submitted for payment must be in accordance with the Audi Warranty Policies and Procedures Manual. Claims are subject to review or audit by Audi Warranty.
Tip:
If both fog lights were replaced at the same time, only one damage report needs to go through Warranty per vehicle.
Required Parts and Tools
Additional Information
All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service manuals for the latest information.