A9419182012749_1

94 Exterior lights, moisture accumulation
94 19 18 2012749/14 December 6, 2019. Supersedes Technical Service Bulletin Group 94 number 17-91 dated
July 31, 2017 for reasons listed below.
Model(s)
Year
VIN Range
Vehicle-Specific Equipment
All except
Audi e-tron
quattro
1996 - 2021
All
Not Applicable
Condition
REVISION HISTORY
Revision
Date
Purpose
14
-
Revised header (Added MY20 and MY21)
13
07/31/2017 Revised header (Added model years)
Revised Condition (Added photo)
Revised Technical Background (Updated information)
Revised Service (Added photos and updated procedure)
12
04/17/2015 Revised header (Added model years)
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 (Figure 1).
Page 1 of 5
© 2019 Audi of America, Inc.
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.
Figure 1. Condensation on the inside of the lights.
Technical Background
The headlight ventilation system allows air from the exterior of the assembly to pass through the headlights. This
open water-protected ventilation system (which is needed for pressure compensation) creates different climate
zones in the headlight: very warm areas, where the lens is warmed up by the light, and relatively cool areas,
where the lens is cooled down by the airflow.
Considerable differences in humidity and temperature between the inside and the outside of the headlights, even
when the car is being driven, can create condensation. While condensation is most common in cold and wet
weather, it can also occur after a car wash, or when the temperature changes. Condensation is more visible on
lenses made of clear glass than on lenses with patterns. The moisture does not affect the headlight function or
light performance, and it does not lead to corrosion or damage to other headlight parts.
Page 2 of 5
© 2019 Audi of America, Inc.
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.
Production Solution
Not applicable.
Service
Always check for TSBs that are specific to your vehicle configuration and specific customer concern. This TSB
only provides a general overview when performing diagnosis, of moisture concerns which are internal to an
exterior lighting assembly.
For the Headlamp:
1. The light emission surface (Figure 2A) of the main beam should be clear after driving 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.
Figure 2. A: Main beam light emission surface. B: Condensation of the headlamp.
Page 3 of 5
© 2019 Audi of America, Inc.
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.
2. If water drops or condensation are present on the light emission surface (Figure 3A) after performing step
one, inspect the headlamp assembly for the root cause:
 Missing cover.
 Damaged seal.
 Clogged drain.
 Outside influence.
Figure 3. A: Main beam light emission surface.
3. Perform repair:
 In cases where the headlamp assembly is not the root cause (clogged drain and/or missing access
cover), dry the headlamp assembly with compressed air.
 Perform a visual inspection of electrical connectors and any control modules attached to the headlight. If
corrosion is found in one of these components, it must be repaired or replaced. Reference the repair
manual for repair instructions.
Tip: It is helpful to take a photo before and after step 1 for visual comparison.
Page 4 of 5
© 2019 Audi of America, Inc.
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.
Warranty
This TSB is informational only and not applicable to any Audi Warranty.
Additional Information
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.
©2019 Audi of America, Inc. 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.
Page 5 of 5
© 2019 Audi of America, Inc.
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.