Technical Service Bulletin
94 Exterior lights have moisture accumulation
94 23 64 2012749/16 May 9, 2023. Supersedes Technical Service Bulletin Group 94 number 21-34 dated
February 17, 2021, for reasons listed below.
Model(s)

Year

VIN Range

Vehicle-Specific Equipment

All Audi Models

2016 - 2024

All

Not Applicable

Condition
REVISION HISTORY
Revision Date

Purpose

16

Revised header (Added MY 23,24)

-

Revised Technical Background (Updated information)
15

02/17/2021 Revised header (Added MY22, models, and attachment)
Revised Service (Added reference to TSB 2061922)

14

12/06/2019 Revised header (Added MY20 and MY21)

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intellectual property rights of Audi of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any time without notice. No part of this
document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may
these materials be modified or reposted to other sites, without the prior expressed written permission of the publisher.

Technical Service Bulletin
Customer states:
• Condensation is visible on the inside of the
headlight, taillight, fog light, side marker light,
front turn signal, daytime running lights, and/or
third brake light lens.
Workshop findings:
• Workshop is able to confirm the customer
concern. Figure 1 provides examples of
NORMAL amounts of moisture that may be
visible. The level of moisture buildup may vary
car-to-car or even between lamps on the same
vehicle.

Figure 1. Normal condensation/moisture on the inside of
the lights.

Technical Background
Process of physical condensation on headlights and tail lights:
In winter and/or in wet weather, the complaint “condensation on the lens, moisture in the lamp” can occur on the
headlights and other exterior lights as there is more humidity in the surrounding air.
Headlights and tail lights are normally open systems meaning air from the outside circulates through the
component. This type of design is necessary to ensure pressure equalization.
When the vehicle is parked after use, the back of the headlight is heated up by residual heat from the engine, for
example, while at the same time, the lens is cooled down by the cold outside air. This creates a temperature
difference which causes the humidity in the air to condense on the inside of the lens.
Driving through a car wash or using a steam cleaner on the engine compartment amplifies this phenomenon by
increasing the humidity in the component.
LED headlights and tail lights:
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intellectual property rights of Audi of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any time without notice. No part of this
document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may
these materials be modified or reposted to other sites, without the prior expressed written permission of the publisher.

Technical Service Bulletin
The lens does not warm up even when the lights are switched on because none of the light emitted is in the
infrared spectrum. In this case, only the pressure difference at the vents occurring while driving provides the
needed airflow to clear up the condensation. The vents are arranged and designed in such a way that the lens will
be cleared after driving with sufficient ventilation.
The normal presence of moisture/condensation:
• Does not affect the performance of the headlight or taillight.
• Does not cause corrosion inside the component.
• Can occur on any lamp.
• May vary depending on environmental conditions and driving habits.
• Is NOT a condition covered under warranty.

Production Solution
Not Applicable

Service
Always check for TSBs that are specific to your vehicle configuration and specific customer concern. This TSB
provides a general overview when performing the diagnosis of moisture concerns that are internal to an exterior
lighting assembly.
Please document this repair following the instructions in TSB 2061922: 94 How to properly document optical
concerns for headlights and tail lights.

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All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and other
intellectual property rights of Audi of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any time without notice. No part of this
document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may
these materials be modified or reposted to other sites, without the prior expressed written permission of the publisher.

Technical Service Bulletin
The light emission surface (Figure 2A) of the main beam
should be clear after driving for approximately 10 minutes
with the main beam on.
• Driving speeds must be consistently over 45mph for the
ventilation system to properly function.
• Residual condensation (Figure 2B) may be present
depending on ambient conditions, this is normal.
• The amount of time required for the condensation to
clear will depend on the outside temperature, relative
humidity, and the vehicle speed (higher speeds provide
better ventilation).
• Leaving a vehicle stationary with lamps on is NOT
sufficient for clearing moisture

Figure 2. A: Main beam light emission surface. B:
Condensation of the headlamp.
If water drops or condensation are present on the light emission surface (Figure 2A) after performing step one,
inspect the headlamp assembly for the root cause:
• Missing cover.

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All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and other
intellectual property rights of Audi of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any time without notice. No part of this
document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may
these materials be modified or reposted to other sites, without the prior expressed written permission of the publisher.

Technical Service Bulletin
• Damaged seal.
• Clogged drain.
• Outside influence.
• Vent tube disconnected from the headlamp.
Tip: Take a photo before and after Step 1 for visual comparison. Please retain photos for at least 1 month
after claim submission.
Note: If there is condensation in the headlights, the light emission surface of the lens must be clear after
the vehicle is driven in such a way as to provide sufficient ventilation (on a major road/motorway) with the low
beam headlamp switched on. The remaining inside surfaces may still have condensation on them after the
drive; this is not a problem.
Normal amounts of moisture:
If the amount of moisture/condensation is deemed normal please explain this to the customer. Parts
replacement will not correct the concern and the customer will likely still experience the same issue.
Abnormal amounts of moisture:
Abnormal amounts of moisture can be seen in figures 3 and 4 below. These are examples of excessive moisture
still present AFTER a thorough test drive with lamps on.
When submitting a claim under warranty, please upload the photos to DOC-IT for review. Claims submitted
without photos may be charged back.

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All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and other
intellectual property rights of Audi of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any time without notice. No part of this
document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may
these materials be modified or reposted to other sites, without the prior expressed written permission of the publisher.

Technical Service Bulletin

Figure 3. A: Example of a compromised headlamp. Moisture is still present in the light emission surface after a
test drive.

Figure 4: Example of compromised tail lamps after a sufficient test drive.

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

Additional Information
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All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and other
intellectual property rights of Audi of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any time without notice. No part of this
document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may
these materials be modified or reposted to other sites, without the prior expressed written permission of the publisher.

Technical Service Bulletin
The following Technical Service Bulletin(s) will be necessary to complete this procedure:
• TSB 2061922, 94 How to properly document optical concerns for headlights and tail lights.
All part and service references provided in this TSB (2012749) 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.
©2023 Audi of America, Inc. All rights reserved. The information contained in this document is based on the
latest information available at the time of printing and is subject to the copyright and other intellectual property
rights of Audi of America, Inc., its affiliated companies, and its licensors. All rights are reserved to make changes
at any time without notice. No part of this document may be reproduced, stored in a retrieval system, or
transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may
these materials be modified or reposted to other sites, without the prior expressed written permission of the
publisher.

© 2023 Audi of America, Inc.

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All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and other
intellectual property rights of Audi of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any time without notice. No part of this
document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may
these materials be modified or reposted to other sites, without the prior expressed written permission of the publisher.