Bulletin No.:

Service Bulletin

Date:

01-08-42-001P
May, 2023

INFORMATION
Subject:

Exterior Lamp Condensation and Water Leak Information and Replacement Guidelines

Models:

2024 and Prior GM Passenger Cars and Trucks (including Medium Duty Trucks)
(Excluding LCF Medium Duty Trucks)

Attention: Involved Region or Country: North America, Europe, Uzbekistan, Russia, Middle East,
Iraq, Israel, Palestine, Argentina, Brazil, Bolivia, Chile, Colombia, Ecuador, Paraguay,
Peru, Uruguay, Venezuela, Japan, Cadillac Korea (South Korea), GM Korea Company,
China, Taiwan, Thailand, Singapore, Philippines, Australia/New Zealand, Egypt, Other
Africa, South Africa
This bulletin has been revised to add the 2024 Model Year and adjust the descriptions of
condensation, leaks and internal coatings. Please discard Corporate Bulletin Number
01-08-42-001O.

Dealers in the U.S. and Canada Only: Please follow
Service Bulletin # 18-NA-306 and the pre-authorization
process prior to warranty replacement of front
headlamps in 2021 and newer model year vehicles.
The following information is being provided to better
define the causes of condensation in exterior lamps
and includes guidelines for determining the difference
between a lamp with a normal atmospheric condition
(condensation) and a lamp with a water leak. If the
lamp is determined to have condensation and not a
leak, this should be explained to the customer and their
lamp should not be replaced in warranty.
Some exterior lamps, such as cornering, turn signal,
backup, headlamps, side marker, fog lamps, or tail
lamps may exhibit a fine mist or white fog
(condensation) on the inside of the lamp lens. This may
be normal during certain weather conditions or
following a carwash.
Condensation occurs when the lens surface, through
atmospheric changes, reaches the “dew point.” When
this takes place, the moisture in the air within the lamp
assembly condenses, creating a fine mist or white fog
on the inside surface of the lamp lens.
Most exterior lamps on General Motors vehicles use a
vented design. They are designed to remove any
accumulated moisture vapor by expelling it through a
vent system. The vent system always operates;
however, it is most effective when the lamps are ON
and when the vehicle is in motion. Depending on the
size, shape, and location of the lamp on the vehicle,
and the atmospheric conditions occurring, the amount
of time required to clear the lamp may vary from 2 to 6
hours. Customers with short commutes will experience
Copyright 2023 General Motors LLC. All Rights Reserved.

a longer time to clear the lamp. If a customer states that
the moisture in their lamp “comes and goes”, this is
likely condensation and not a leak and the lamp should
not be replaced.

Condensation Examples (Do Not
Replace Lamp Assembly Under
Warranty)

3789054

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May, 2023

Bulletin No.: 01-08-42-001P

3789057

6267309

A Fine Mist or White Fog on the Inside Surface of
the Lamp Lens Occurring After a Period of High
Humidity
Important: Moisture is most noticeable during the
Spring and Fall of each year, due to high humidity and
the large fluctuation in temperature between day and
night.
Note: Any of the conditions listed below would indicate
NOT to service / replace the lens or lamp assembly.
•

6267308

May be located primarily in the lens corners or
edges
• The condition should clear of moisture when the
vehicle is parked in a dry environment, or when
the vehicle is driven with the lights ON. Place the
vehicle in a dry environment and turn on the lights
for 60 minutes. Do not replace the lamp if the
condition has significantly improved after 60
minutes.
• A comparison of the equivalent lamp on the
opposing side of the vehicle indicates a SIMILAR
performance. (Condensation can occur in one or
both lamps. Leaks are more likely to occur on one
side at a time.)
Note: A different performance of lamps on opposite
sides of a vehicle DOES NOT always indicate that one
lamp is bad, and the other is normal. For example, on a
cold day when the sun is hitting only one side of the
vehicle, the normal condition of one side showing clear
and the other showing fogging/moisture, could be
misinterpreted as a bad lamp. The customer may

Bulletin No.: 01-08-42-001P

May, 2023

Page 3

comment that, or you may need to inquire if, the
moisture “comes and goes.” Moisture “coming and
going” is considered a normal condition.
If the above conditions are noted, the customer should
be advised that replacement of a lamp assembly may
not correct this condition as it is likely a function of
weather / other conditions outside the vehicle. The
lamp assembly should not be replaced under warranty
for this reason.

Water Leak Examples

3789063

Numerous & Various Size Drops of Water Collecting
on the Inside Surface of the Lamp Lens
Note: Any of the conditions listed below would indicate
the need to service the lens or lamp assembly.
•

3803382

3789062

An accumulation of water in the bottom of the
lamp assembly.
• A condition that WON'T clear when the vehicle is
parked in a dry environment, or when the vehicle
is driven with the lights ON.
• A comparison of the equivalent lamp on the
opposing side of the vehicle indicates a different
performance.
Note: A different performance of lamps on opposite
sides of a vehicle DOES NOT always indicate that one
lamp is bad, and the other is normal. For example, on a
cold day when the sun is hitting only one side of the
vehicle, the normal condition of one side showing clear
and the other showing fogging/moisture, could be
misinterpreted as a bad lamp. The customer may
comment that, or you may need to inquire if, the
moisture “comes and goes.” Moisture “coming and
going” is considered a normal condition.

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May, 2023

Bulletin No.: 01-08-42-001P

Internal Coating Issues Examples

5864718

Bulletin No.: 01-08-42-001P

May, 2023

Page 5

5864713

Permanent Staining on the Inside Surface of the
Lamp Lens
• Some General Motors lamps have a coating on
the inside of the lens to reduce condensation.
Occasionally, there will be an issue where this
coating is no longer clear, but instead is always
visible.
Important: This failure mode is internal to the lamp
lens, if you can feel an issue when running your
finger along the outer lens of the headlamp, it is not
an issue with the internal coating streaking.
Note: Any of the conditions listed below would indicate
the need to service the lens or lamp assembly.

repair. Most likely the customer has no idea they are
not original equipment, as the initial appearance is
generally good. Obviously, these parts are not covered
by warranty. Some of the common company names
seen on these lamps are Eagle Eyes, Srumto,
and Depo.

•

The customer reports they have a PERMANENT
stain on the INSIDE of the lens. The stain never
goes away, even when the condensation / water
inside the lamp is cleared.
If a lamp is found to be exhibiting a leak, review the
most recent version of Service Bulletin
02-08-42-001 for information regarding impact
damage and modification inspection.
Non-GM Headlamp, Tail Lamp and Fog Lamp
Assemblies
Many companies outside of General Motors are
manufacturing lamp assemblies that look very similar to
original equipment. They target high volume programs.
These lamps are most often presented by customers as
holding moisture or for inoperative functions due to
corroded electrical connections. It appears these non
OE lamps get installed on vehicles as part of a collision

2650251

This fog lamp was returned for retaining moisture. As
you can see it is marked with the Depo brand (it is also
called out on the front lens).

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May, 2023

Bulletin No.: 01-08-42-001P

The most reliable way to identify a non OE part is to
compare it to the replacement service part or a like
vehicle. Many do have the application called out on the
part with the letters GM being present but would not
typically use a GM trademark. They often use
substandard wiring, sockets, vent patches and
unsealed connectors.
Example of GM Trademark
Note: The graphics below are examples of GM
Trademarks that appear on GM lamp assemblies.
Current assemblies contain a GM trademark in multiple
locations including on a label affixed to the assembly
and in the approval marking.

6340829

3803767

6340827

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper
service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a
job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
information.

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