File in Section:

Service Bulletin

01 - HVAC

Bulletin No.:

99-01-39-004E

Date:

February, 2014

TECHNICAL
Subject:

Air Conditioning Odor (Install Evaporator Core Dryer Kit and Apply Cooling Coil
Coating)

Models:

2014 and Prior GM Passenger Cars and Trucks
All Equipped with Air Conditioning

This bulletin has been revised to add the 2013 and 2014 model year and update the
Labor Operation to the Global Labor Code (GLC). Please discard Corporate Bulletin
Number 99-01-39-004D.

Condition
Some customers may comment about musty odors
emitted from the Heating, Ventilation and Air
Conditioning (HVAC) system at vehicle start-up in hot,
humid conditions.

Cause
This condition may be caused by condensate build-up
on the evaporator core, which does not evaporate by
itself in high humidity conditions. The odor may be the
result of microbial growth on the evaporator core. When
the blower motor fan is turned on, the microbial growth
may release an unpleasant musty odor into the
passenger compartment.
There are several other possible sources of a musty
odor in a vehicle. A common source is a water leak into
the interior of the vehicle or foreign material in the
HVAC air distribution system. Follow the procedures in
SI for identifying and correcting water leaks and air inlet
inspection.
The procedure contained in this bulletin is only
applicable if the odor source has been determined to be
microbial growth on the evaporator core inside the
HVAC module.

Correction
Many vehicles currently incorporate an afterblow
function within the HVAC control module software. The
afterblow feature, when enabled, employs the HVAC
blower fan to dry the evaporator after vehicle shut down
and this function will inhibit microbial growth.
Technicians are to confirm that the customer concern is
evaporator core odor and that the vehicle has the
imbedded afterblow feature, as defined in the SI
document for that specific vehicle model, model year
and specific HVAC option. Refer to SI for enabling the
afterblow function. Vehicles being delivered in areas

Copyright 2014 General Motors LLC. All Rights Reserved.

prone to high humidity conditions may benefit from
having the afterblow enabled calibration installed prior
to any customer comment.
Important: If the vehicle is not factory equipped with
the imbedded afterblow enable feature, it may be
added with the Electronic Evaporator Dryer Module Kit
(P/N 12497910 or AC Delco 15–5876).
Important: When installing the Electronic Evaporator
Dryer Module, you MUST use the included electrical
splice connectors to ensure a proper splice. Complete
detailed installation instructions and self testing
procedures are supplied with the kit. If necessary, the
Electronic Evaporator Dryer Module may be installed
underhood if it is protected from extreme heat and
water splash areas.
To immediately remove the evaporator core odor on all
suspect vehicles, it is necessary to eliminate the
microbial growth and prevent its re-occurrence. To
accomplish this, perform the following procedure:
Vehicle and Applicator Tool Preparation
1. The evaporator core must be dry. This may be
accomplished by disabling the compressor and
running the blower fan on the recirc heat setting for
an extended period of time.
Note: Compressor engagement will cause the
evaporator core to remain wet and will prevent full
adherence of the Cooling Coil Coating to the
evaporator core surfaces.
2. Verify that the air conditioning drain hose is not
clogged and place a drain pan beneath the vehicle.
3. Place a protective cover over the carpet below the
evaporator core.
4. Remove the cabin air filter, if equipped, and cover
the opening prior to applying the Cooling Coil
Coating, as the product may clog the filter. If the
cabin air filter appears to have little or no remaining
life, suggest a replacement to your customer.

Page 2

February, 2014

5. If the HVAC module has a blower motor cooling
tube, be careful NOT TO SPRAY THE COOLING
COIL COATING INTO THE BLOWER MOTOR
COOLING TUBE.
6. Attach the Flexible Applicator Pressure Spray Tool
(J-43810–20A) to a compressed air line operating
at 586 kPa (85 psi) to 793 kPa (115 psi).
7. Shake the bottle of Cooling Coil Coating well.
Screw the bottle onto the cap on the applicator
tool's pick-up tube.
Note: The pick-up tube is designed for 120 ml (4 oz)
and 240 ml (8 oz) bottles and should coil slightly in the
bottom of a 120 ml (4 oz) bottle.
8. Use one of the following three methods to apply
the Cooling Coil Coating.
Important: If the Pressure Applicator Spray Tool
(J-43810–20A) is not available, the Cooling Coil
Coating is also available in an aerosol can
(P/N 12377952 (in Canada, 10953503)).
Application Through Blower Motor Control
Module Opening
• Remove the blower motor control module
(blower motor resistor). Refer to the applicable
procedure in SI.
• Clean any debris or foreign material from inside
the HVAC module and on the evaporator core
surface.
• Apply the Cooling Coil Coating directly to the
evaporator core through the blower motor
control module (blower motor resistor) opening.
• Use the flexible wand to direct the Cooling Coil
Coating over the entire evaporator core and
surrounding gasket surfaces.
• When the application is complete, install the
blower motor control module (blower motor
resistor).
Application Through Blower Motor Opening
• Remove the blower motor. Refer to the
applicable blower motor removal procedure
in SI.
• Clean any debris or foreign material from inside
the HVAC module and on the evaporator core
surface.
• Apply the Cooling Coil Coating directly to the
evaporator core through the blower motor
opening.
• Use the flexible wand to direct the Cooling Coil
Coating over the entire evaporator core and
surrounding gasket surfaces.
• When the application is complete, install the
blower motor.

9.

10.

11.
12.
13.
14.
15.

Bulletin No.: 99-01-39-004E

Application Through a Hole in the HVAC
Module
• If neither of the two previous application
methods are available, it may be necessary to
drill a hole in the HVAC module.
• Locate an area of the HVAC module between
the blower motor and the evaporator core. Drill
a 10 mm (3/8 in) hole in the HVAC module. Use
caution to keep the drill clear of the evaporator
core and the blower motor fan.
• With the air distribution vents closed and the
blower motor fan speed on HIGH, insert the
applicator tool into the hole and spray the
Cooling Coil Coating into the airstream toward
the evaporator core.
• Use a GM approved RTV sealant to plug the
hole in the HVAC module.
After the Cooling Coil Coating application is
complete, start and run the vehicle for
approximately 10 minutes, with the compressor
disabled, HVAC mode set to Recirculate/Max, heat
set to full warm, blower motor fan speed on high,
and one window open approximately 12 mm
(1/2 in). This cures the Cooling Coil Coating onto
the evaporator core surface.
While the engine is running, rinse the applicator
tool with warm water to prolong the life of the tool.
Be sure to spray warm water through the nozzle to
rinse out any residual Cooling Coil Coating still in
the capillary pick up tube, otherwise it will dry and
clog the applicator tool. Also remove the small
green valve from the bottle cap and rinse it
thoroughly while rolling it between two fingers and
then reinstall it. If this valve is clogged , the Cooling
Coil Coating will not flow through the
applicator tool.
Shut off the engine and enable the compressor
again.
Verify proper HVAC system operation.
Remove the protective cover from inside the
vehicle.
Remove the drain pan from underneath the
vehicle.
Reinstall the cabin air filter if necessary.

Bulletin No.: 99-01-39-004E

February, 2014

Page 3

Parts Information
Important: The Cooling Coil Coating listed below is
the only GM approved product for use under warranty
as an evaporator core disinfectant and for the long term
control of evaporator core microbial growth.
Part Description

GM Part Number

Bosch Part Number

Cooling Coil Coating (CCC) Kit
(with flexible applicator tool and 1 bottle
of Cooling Coil Coating)

12346391

J-43810-A

Cooling Coil Coating Flexible Applicator
Tool only

N/A

J-43810-20A

Refill for Cooling Coil Coating Applicator
Kit (1 x 120 ml (4 oz) Bottle of CCC)

N/A

J-43810-30

Cooling Coil Coating (1 x 180 ml (6 oz)
Aerosol Can of CCC)

12377952 (In Canada use 10953503)

N/A

Electronic Evaporator Dryer Module Kit
(one per vehicle)

12497910 (AC Delco 15–5876)

N/A

Warranty Information
For vehicles repaired under warranty, use:
Labor
Operation
4480118*

Description
Apply Cooling Coil Coating and
Install Electronic Evaporator
Dryer Kit

Labor
Time
0.8 hr

*This is a unique labor operation for bulletin use only. It will
not be published in the Labor Time Guide.

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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