Bulletin No.:

Service Bulletin

Date:

07-08-42-006O
July, 2020

INFORMATION
Subject:

Information on Available BCM Calibrations to Restore Bulb Outage Detection on
Vehicles Produced by a Second Stage Manufacturer (Upfitter), Turn Signals Flash Fast
after Factory Box Removed

Models:

2007-2018 Chevrolet Silverado
2019 Chevrolet Silverado LD
2019 Chevrolet Silverado 1500 (New Model)
2019 Chevrolet Silverado 2500/3500
2020 Chevrolet Silverado 1500
2020 Chevrolet Silverado 2500HD/3500HD
2007-2018 GMC Sierra
2019 GMC Sierra Limited
2019 GMC Sierra 1500 (New Model)
2019 GMC Sierra 2500/3500
2020 GMC Sierra 1500
2020 GMC Sierra 2500HD/3500HD

Attention: This Bulletin also applies to any of the above models that may be Export from North
America vehicles.
This Bulletin has been revised to add the 2019 and 2020 T1 Truck Models. Please discard
Corporate Bulletin Number 07-08-42-006N.

•

The information contained in this bulletin applies
only to 2500 and 3500 Series trucks that are to be
completed by a second stage manufacturer
(upfitter) and may need to have the Body Control
Module (BCM) rear turn signal bulb outage
detection capability changed.
• 2014 and earlier 1500 Series trucks only have
Option #1 available.
Production vehicles will be manufactured with one
of the following BCM rear turn signal bulb outage
detection software options:
Notice: Option #1 is the only option available for
2014 and earlier 1500 Series trucks and is included
with all trucks equipped with a pickup box
(RPO E63).
1. A standard production vehicle will have BCM
software that checks for two bulbs functioning in
each rear turn signal bulb circuit. If one or more
bulbs are inoperative, the BCM will “fast flash” the
Instrument Panel Cluster (IPC) turn signal indicator
as required by Federal Motor Vehicle Safety
Standard (FMVSS) 108 and Canada Motor Vehicle
Safety Standard (CMVSS) 108.

Copyright 2020 General Motors LLC. All Rights Reserved.

Notice: Option #2 is available for 2014 and older
2500 and 3500 Series trucks.
2. Certain 2500 and 3500 models can be ordered with
a new option (RPO 9U5) where the BCM checks
for one bulb functioning in each rear turn signal
bulb circuit. If the bulb goes inoperative, the BCM
will “fast flash” the Instrument Panel Cluster (IPC)
turn signal indicator as required by Federal Motor
Vehicle Safety Standard (FMVSS) 108 and
Canada Motor Vehicle Safety Standard
(CMVSS) 108.
Notice: Option #3 is available for 2015, 2016, 2017,
2018, 2019 and 2020 trucks (available on trucks with
box delete ZW9).
3. Models built with a pickup box delete or chassis
cab option (RPO ZW9) will be produced with a
BCM program that has no turn signal bulb outage
detection capability (LED compatible). The IPC
turn signal indicator will flash at the same rate no
matter how many turn signal bulbs are inoperative.

Page 2

July, 2020

Note: For 2015, 2016, 2017, 2018, 2019 and 2020
trucks, B3951 & B3950 DTCs for rear tail lamps could
set on any truck (ZW9 or E63) if LED lamps are
installed (or lamps are inoperative). This code is used
as an assembly verification but does not affect the
function of a properly operating system with LED lights
installed.
In some cases, the upfitter may wish to change the turn
signal bulb outage detection capability so that the turn
signals work correctly with their upfit or to meet certain
requirements. This will require contacting the Techline
Customer Support Center (TCSC) (1-800-828-6860
English or 1-800-503-3222 French) to open a case and
obtain a Vehicle Configuration Index (VCI) number.
Advise the TCSC consultant which turn signal bulb
outage detection capability is needed from the
following list:
1. Factory standard production TWO bulb outage
detection.
Notice: Only available on certain Model Year
2007-2013 2500 AND 3500 Series vehicles.

Bulletin No.: 07-08-42-006O

2. Optional (RPO 9U5) ONE bulb outage detection.
Notice: This option is only available on certain
Model Year 2007-2014 2500 AND 3500 Series
vehicles.
3. NO bulb outage detection (LED compatible).
Notice: This option is only available on 2015, 2016,
2017, 2018, 2019 and 2020 trucks and is included on
trucks built with the RPO ZW9 box delete option.
The BCM can then be reprogrammed with the correct
software.

Warranty Information
As with any vehicle modifications these changes and
expenses (from TCSC, parts, labor or other expenses)
should not be considered warrantable repairs and
should not be charged under warranty. These
modifications are considered customer pay. No labor
operation is provided.

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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