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Information on BCM Calibrations Available to Restore Bulb Outage Detection on Vehicles Produced by a Second Stage Manufacturer (Upfitter)

Subject:Information on BCM Calibrations Available to Restore Bulb Outage Detection On Vehicles Produced By A Second Stage Manufacturer (Upfitter)

Models:2007-2008 Chevrolet Silverado
2007-2008 GMC Sierra
Chassis Cab Models and Pickups with Box Delete Option Only (RPO ZW9)



This bulletin is being revised to add the 2008 model year. Please discard Corporate Bulletin Number 07-08-42-006 (Section 08 -- Body and Accessories).


The information contained in this bulletin only applies to vehicles 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 restored. The ability of the BCM to detect a rear turn signal bulb outage is intentionally deleted on chassis cab models and pickups with box delete option (RPO ZW9). All production vehicles will be manufactured with one of the following BCM rear turn signal bulb outage detection software options:

  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.
  2. A vehicle built with a pickup box delete or chassis cab option will be produced with a BCM program that has no turn signal bulb outage detection capability. The IPC turn signal indicator will flash at the same rate no matter how many turn signal bulbs are inoperative.

The responsibility for compliance with FMVSS 108 and CMVSS 108 in regards to turn signal bulb outage detection lies with the second stage manufacturer (upfitter) on remanufactured vehicles. In some cases the upfitter may wish to restore the turn signal bulb outage detection capability, as described in option 1 above, to assure compliance with FMVSS 108 and CMVSS 108. 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. The BCM can then be reprogrammed with the software that enables rear turn signal bulb outage detection capability.