PI0987

File in Section:
Service Bulletin
Bulletin No.:
Date:
PI0987
June, 2013
PRELIMINARY INFORMATION
Subject:
Passenger Side Defrost Air Flow/Performance and/or Temperature Less Warm Than
Drivers Side in Defrost, IP Vent or Heat Modes
Models:
2012-2013 Cadillac Escalade Models
2012-2013 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2012-2013 GMC Sierra, Sierra Denali, Yukon Models
Excluding Crew Cab and Extended Cab with Single Zone Air Conditioning (RPO C67)
Condition/Concern
Some customers may comment that the passenger side defrost air flow/performance and/or the temperature is less
warm than the drivers side in defrost, IP vent or heat modes. Even with this condition, the vehicle will meet all
requirements.
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The cause of this condition may be that the belt seal (1) that goes around the heater core may have become
mis-positioned. If this occurs, it can create a path for air to travel to the wrong side of the HVAC Module.
Recommendation/Instructions
Preliminary Inspection Procedure
The intent of this inspection procedure is to gain visual access to the heater core belt seal without removing the IP,
HVAC module and heater core. Visual access to the heater core is attained by drilling a hole in the lower HVAC case
and using a borescope, or equivalent, following the steps below.
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1. Remove the instrument panel insulator (1). Refer to Instrument Panel Insulator Replacement in SI.
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2. If equipped, remove the left side front floor console side trim panel (1). Refer to Front Floor Console Side Trim
Panel Replacement - Left Side in SI.
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3. Remove the instrument panel lower brace bezel and center support bracket (1). Refer to Instrument Panel
Center Support Bracket Replacement in SI.
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Important: The mark for the hole location should be in line with the standing rib on the bottom side of the
HVAC case.
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4. Note the position of the lower HVAC case and mark a location to drill a hole in the case on the rounded corner
facing the driver footwell area. The mark should be approximately 13 mm (0.50 in) upward from the bottom
surface of the case.
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Important: Set the drill stop 19 mm (0.75 in) from the point of the drill bit to prevent drilling too deep and possibly
damaging the heater core.
5. Using a 3/8” drill bit with a stop, set at max 3/4” depth hole, drill an access hole (1) at the marked location on
the case.
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6. Insert the borescope (1) and look to see the position of the horizontal belt seal around the heater core.
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• If the belt seal (1) is rolled or mis-positioned (as shown in the graphic above), install the push pin to the
drilled access hole in the HVAC case as described in step #7, then R&R the heater core and replace the
heater core belt seal following Heater Core Replacement in SI.
• If the belt seal is properly positioned, complete steps #7-10, then refer to SI for any further recommended
HVAC diagnostics.
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Important: To improve sealing of the plugged hole, apply a small amount of RTV, GM P/N 12378521 (in Canada, P/
N 88901148), or equivalent, to the push pin prior to installation.
7. Install a push pin (1), Kent Automotive Push Retainer P/N P20681, or equivalent, into the access hole drilled
into the HVAC case.
8. Install the instrument panel center support bracket and the lower brace bezel. Refer to Instrument Panel Center
Support Bracket Replacement in SI.
9. If equipped, install the left side front floor console side trim panel. Refer to Front Floor Console Side Trim Panel
Replacement - Left Side in SI.
10. Install the instrument panel insulator. Refer to Instrument Panel Insulator Replacement in SI.
Parts Information
Part Number
Description
P20681
*Kent Automotive Push Retainer
89018784
SEAL KIT, HTR & A/C EVPR & BLO MDL
*We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials.
General Motors does not endorse, indicate any preference for, or assume any responsibility for the products or material from this
firm or for any such items that may be available from other sources.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Description
4480038*
Preliminary Heater Core Seal Inspection Procedure
0.5 hr
4413660
Heater Core Replacement
Use Published
Labor
Operation Time
*This is a unique labor operation for bulletin use only. It will not be published in the Labor Time Guide.
Labor Time