Lighting - Water In Fog Lamps
94 Water in fog light
94 10 32
2020049/2
August 10, 2010
Supersedes Technical DIAGNOSIS AND REPAIR Group 94 number 09-07 dated February 26, 2009 for reasons listed below.
Affected Vehicles
CONDITION
427
^ The customer may report water in the front fog lights.
^ A headlight warning symbol may appear in the IP cluster display.
TECHNICAL BACKGROUND
Because of the high operating temperatures of the bulbs, lights are constructed as open, breathing systems. As a result, humid air (from fog, when
driving in rain, etc.) can get into the lights.
The front fog lights have two vents to keep them dry. When driving, increased pressure is applied to one vent and a slight vacuum is applied to the
other vent. This ensures air circulation in the lights to speed the drying of humid lights. Switching on the light also speeds up drying.
Water may enter through the vents when driving through deep water For such cases, specific retrofitting kits for the front fog lights are available.
With the retrofitting kit, one opening is closed watertight, and a water-repellent element is installed on the second opening. The water-repellent
element allows pressure compensation but is watertight.
Tip: If humidity gets into the special fog light after bulb replacement, it will stay because of the missing ventilation system. In this case, the fog light
has to be dried manually.
PRODUCTION SOLUTION
Not applicable.
SERVICE
1. Clean steamed-up front fog lights (Figure 2) according to TSB 2012749.
2. Check the seal of the fog lamp for damage after completing TSB 2012749.
^ If there is strong dripping, replace the front fog lights without retrofitting kit.
428
^ In case of major water ingress (Figure 3) or massive corrosion of the reflector, replace the front fog lights with water-repellent elements and plugs.
Two elements and two plugs are included in retrofitting kit 8R0 998 109. One retrofitting kit is enough for both front fog lights.
Standard A6 front fog lamp: Install the water-repellent element and the plug as shown in Figure 4.
S line of front fog lights: Install the water-repellent element and the plug as shown in Figure 5.
429
WARRANTY
REQUIRED PARTS AND TOOLS
ADDITIONAL INFORMATION
The following Technical DIAGNOSIS AND REPAIR(s) will be necessary to complete this procedure:
^ TSB 2012749 94 Exterior lights, moisture accumulation
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.
