VACUUM FLUORESCENCE DISPLAYS FLICKER OR GO BLANK

SUBJECT: VACUUM FLUORESCE R OR GO BLANK POSSIBLY SETTING A CODE E047

MODELS AFFECTED: 1986-1991 ELDORADOS AND SEVILLES

This bulletin supersedes Service Bulletin T-91-44, Group 8, which should be discarded. This bulletin is being revised to correct art work.

Some 1986-1991 Eldorados and Sevilles may experience a condition of vacuum florescence displays flickering or going blank with a code E047 possibly being set. This may be the result of a loss of power or ground to the Instrument Panel Cluster (IPC), Climate Control Driver Information Center (CCDIC), or radio.

The Central Power Supply (CPS) provides power (7 and 12 volts) and ground to the IPC, CCDIC, and Body Control Module (BCM). If the BCM loses power from the CPS, the ECC will not respond to key selections and twilight sentinel will become inoperative. Within the IPC there is a regulator which provides 55 volts for the Vacuum Fluorescence (VF) displays of the IPC, CCDIC, and 16 volts to the radio. If the IPC loses power from the CPS, the IPC and CCDIC VF displays will go blank. The VF displays will also go blank if the IPC, CCDIC, or radio experience an internal condition which will cause the regulator within the IPC to turn off to protect itself. To diagnose and repair this condition use the trouble tree in Figure 1.

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.