The B: Instrument Cluster's C2 Pinout Test, found in the service manuals listed below, has been revised to avoid any confusion and misdiagnosis.
1991 Ninety Eight, page 8A-82-18 1992 Ninety Eight, page 8A-82-18 1992 Eighty Eight, page 8A-82-18 1993 Eighty Eight/Ninety Eight, page 8A-82-21
Please update your respective service manual accordingly with the following revised text for proper system diagnosis.
The text which states:
CONNECTOR TERMINAL B1 - NOT USED
Should be replaced with:
CONNECTOR TERMINAL B1 - ILLUMINATED INPUT, VARIABLE VOLTAGE WITH LAMPS ON AND DIMMER CONTROL ADJUSTED. REFER TO SECTION 8A-117 B1 GRY (8).
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.