2021-2026 Audi Models Exterior Light Moisture TSB

Audi has released Technical Service Bulletin (TSB) 2012749/18 to address concerns about moisture accumulation in the exterior lights of various 2021-2026 Audi models. This bulletin helps technicians and owners differentiate between normal physical condensation and actual water leaks, which require different approaches. This information is particularly relevant if you notice 2021 Audi e-tron exterior light moisture.

The TSB outlines two distinct situations regarding moisture in headlights, taillights, side repeater lights, and fog lights.

Symptoms of Exterior Light Moisture

Owners may observe different types of moisture accumulation in their vehicle's exterior lights:

• Physical Condensation (Situation 1): This appears as a fine mist or light fogging on the inside of the lenses. Examples include "Water in left-side headlight" or "Drops forming on left-side lens" that dissipate over time.
• Water Ingress/Leaks (Situation 2): This involves more significant water marks or large droplets that do not clear up, indicating a leak due to issues like open covers or damaged seals. This can also manifest as cosmetic issues such as a "Left reflector tarnished" or "Right reflector tarnished" appearance in side repeater lights or brake lights.

Identifying the Cause: Condensation vs. Leaks

It's crucial to distinguish between these two conditions, as only leaks are considered a fault requiring repair.

Physical Condensation

Condensation is an optical phenomenon that occurs due to temperature differences and humidity. Headlights and taillights are designed as open systems to allow for pressure equalization, meaning outside air circulates through them. This can lead to humidity inside the light assembly, which condenses on the cooler lens surface.

Key characteristics of physical condensation:

• It does not affect the performance of the headlights or taillights.
• It does not cause corrosion inside the component.
• It can occur on any headlamp, fog lamp, or taillight.
• It typically clears up after driving the vehicle for approximately 10-30 minutes at an average speed of 50 mph with the low beam lamp switched on, allowing for sufficient ventilation. Some remaining condensation on inside surfaces after driving is considered normal.

Water Ingress/Leaks

Leaks, on the other hand, are caused by physical damage such as open covers, damaged cap seals, or other component failures. These result in persistent water marks or large droplets that do not dissipate with normal driving. If you observe 2021 Audi e-tron exterior light moisture that fits this description, it likely indicates a leak.

Important Warnings for Owners

Audi TSB 2012749/18 provides critical information for owners:

• "Situation 1: There is condensation on the inside of the lenses (physical condensation – Not a fault which is covered under warranty)."
• Physical condensation "Is NOT a fault which is covered under warranty."
• "Replacing the headlight or taillight will not solve the issue" if the issue is only physical condensation.
• "If a headlight/taillight is replaced because of water ingress/leaks, physical condensation can of course still occur on the new part. This is not the same as renewed water ingress and does not justify replacing the part."

Repair Procedure Summary for Leaks (Situation 2)

For confirmed cases of water ingress or leaks (Situation 2), the TSB outlines a repair process for technicians:

1. Diagnosis: Technicians must use a specific checklist, test plan flowchart, and reference photos (attachments to the TSB) to accurately determine the cause of the moisture.
2. Drying: The affected headlight or taillight should be dried using filtered, oil-free compressed air.
3. Component Replacement: The component identified as the source of the leak must be replaced. Technicians are also instructed to check for and address any corrosion on connectors or control unit connections.
4. Documentation: All repairs must be documented following the instructions in TSB 2061922, titled "94 How to properly document optical concerns for headlights and taillights." Photos of the moisture are required for any warranty claim.

What Owners Should Do

If you observe moisture in your Audi's exterior lights, first try to determine if it's condensation or a persistent leak. Drive your vehicle at highway speeds with low beams on for 10-30 minutes. If the moisture clears, it's likely normal condensation and no repair is needed or covered under warranty. If the moisture persists, or if you see large droplets or water marks, it may indicate a leak. In such cases, contact an authorized Audi service center for diagnosis. Be prepared to provide photos of the issue, as these may be required for warranty claims related to 2021 Audi e-tron exterior light moisture or other affected models.

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NHTSA ID: 11017625