94 Optical Concerns With Tail Lights (GROUP 94, NO. 24-82)

94 OPTICAL CONCERNS WITH TAIL LIGHTS

TECHNICAL SERVICE BULLETIN

SERVICE INFORMATION

94 24 82 2074347/1 June 28, 2024.

Model(s)	Year	VIN Range	Vehicle-Specific Equipment
All Audi Vehicles	2005 - 2025	All	Not Applicable

CONDITION

This service information shows various examples of damage to the taillights where the cause is not covered under warranty.

Concern 1. Light damaged or cracked due to influence of aggressive substances (Figures 1, and 2). 

Customer statement: 

Taillights in side panel, rear lid and/or bumper have visual damage and/or cracks (severe in some cases).

Workshop findings: 

No external application of force can be detected. No contact between light and vehicle body.

Concern 2. Light damaged or cracked due to external application of force (Figure 3). 

Customer statement: 

• Cracks in taillight lens, often in center of the lens.
• Lens broken.
• Cracks on outside of lens
• Leak/water in taillight.

Workshop findings: 

• The complaint can be verified.
• In some cases, no other damage can be detected on the vehicle.
• Water/water droplets can be detected in the taillight cluster. A leak can be detected between the lens and the headlight housing.

TECHNICAL BACKGROUND

Concern 1: Light damaged or cracked due to influence of aggressive substances. 

Aggressive substances may damage the taillights, in some cases substantially. They penetrate the plastic of the lens and lead to cracks. This depends on the substance's components and concentration, the exposure time, the interior temperature of the lights and the outside temperature (including exposure to sunlight).

Examples of substances causing the issue may be:

• Washer fluid with an increased proportion of anti-freeze additive (vehicles with rear window wiper).
• Undiluted washer fluid or anti-freeze additive (vehicles with rear window wiper).
• Window de-icer.
• Aggressive or too highly concentrated cleaning agents in car washes.
• Aggressive general care products (polish) and cleaning agents.
• Please note that the taillights are not suited for polishing as this attacks the outer layer of the lenses and such substances can then penetrate the plastic more easily.

Concern 2: Light damaged or cracked due to external application of force 0 

• An external application of force such as an impact to the lens or a rear collision may result in cracks on the taillight lens or cause the welded joints for the lens and headlight housing to break.
• Such damage to the lens or the welded joints can lead to water getting into the light.

PRODUCTION SOLUTION

Not applicable.

SERVICE

Concern 1: Light cracked due to influence of aggressive substances. 

If there are cracks which are identical, or similar to those in the above photos, the cause is likely to be the influence of aggressive substances.

Further indications that aggressive cleaning agents have been used are:

• Cracks in multiple taillights on individual vehicles
• Residual polish on the taillights and vehicle body.
• The black light housing has white discoloration near the crack on the lens (chemical reaction to aggressive substances).
• This may have been caused by the washer fluid mixture being too strong. Please explain to the customer that the proportion of anti-freeze additive in the windscreen washer system must be adapted to the operating conditions. An excessive proportion of anti-freeze additive in the washer fluid may damage the taillights in the event of contact. Ideally, an Audi Genuine washer fluid should be used. When the outside temperatures are sufficiently warm, a washer fluid without anti-freeze additive should ideally be used in the specified dosage.
• Aggressive cleaning agents e.g., with a high proportion of alcohol, should also not be used. This would make it easier for cracks to form on the taillights, especially if the cleaning agents have time to take effect at high outside temperatures or under exposure to sunlight.
• Please explain the possible causes specified above to the customer.

General information about the use of cleaning/care products can be found in the Owner's Manual. 

Concern 2: Light damaged or cracked due to external application of force. 

If there are cracks which are identical, or similar to those in the photos above, these are likely to have been caused by external application of force.

The following checks should be performed on the vehicle in order to confirm whether external application of force caused the damage:

• Check vehicle body for damage.
• Check vehicle body/bumper cover in area of taillight cut-out for general damage and/or paintwork damage.
• Check vehicle underbody, especially bottom of bumper cover, for general damage and/or paintwork damage (if the vehicle underbody makes contact with the ground, the bumper cover may press against the light and result in cracks in the light's lens).
• If welded joint between lens and housing is broken, check taillight lens for paintwork damage.

Cracks which are due to tension in the component e.g., component deformation or installation under tension, generally start at the outer edge of the lens and work their way inwards. Cracks in the center of the lens normally indicate that no tension is involved. 

WARRANTY

This TSB is informational only and not applicable to any Audi Warranty.

Required Parts and Tools Claims for part replacements outlined within this TSB will not be reimbursed.

For claims unrelated to this TSB, photo documentation is required for review.

• Please take photos of the customer concern and upload them into DOC-IT with the repair order.
• Photos should be documented as outlined in TSB 2061922 94: How to properly document optical concerns for headlights and taillights. 

ADDITIONAL INFORMATION

All part and service references provided in this TSB (2074347  ) are subject to change and/or removal. Always check with your Parts Department and/or ETKA for the latest information and parts bulletins. Please check the Repair Manual for fasteners, bolts, nuts, and screws that require replacement during the repair.

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