Instrument Panel Display - Flickers or Goes Blank

91cadillac01

Bulletin No. T-91-44A
File in Group 8
Number 132
Corp. Ref. No. 118102
Date March, 1991


SUBJECT: VACUUM FLUORESCENCE DISPLAYS FLICKER 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 BCS4 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.

Figure 1 - Vacuum Fluorescence Displays Flicker Or Go Blank Diagnosis:

Figure 2 - CCDIC and IPC VF Displays Are Flashing or Blank With Ignition ON:

To diagnose and repair this condition use the trouble tree in Figure 1.