A new twilight sentinel module, P/N 5976634, has been released to service the above vehicles and is currently available from GMSPO. This module has been revised to prevent repeat failures due to electrical system transients. A twilight sentinel module failure will not cause a loss of headlights while driving.
Refer to the Service Manual Section 8A and 9C for twilight sentinel diagnosis and Section 8C and 9C for replacement procedures.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those 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 a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.