Based off of what you have said and I am understanding what you said, there seems to be a Technical Service Bulleting out on this. I have attached it for your review.
There may be a loss of power or ground.
Bulletin .No. T-91-38
File in Group 8
Corp. Ref. No. 018126
Date Jan. 1991
SUBJECT: VACUUM FLUORESCENCE DISPLAYS FLICKER OR GO BLANK
MODELS AFFECTED: 1985-1991 DE VILLES AND FLEETWOODS
Some 1985-1991 DeVilles and Fleetwoods may experience a condition of vacuum florescence displays flickering or going blank and the Electronic Climate Control (ECC) blower going off. This may be the result of a loss of power or ground to the Body Control Module (BCM) or an internal problem with the Digital Instrument Cluster (DIC), ECC, Fuel Data Panel (FDP), or ECC power module/blower.
Within the BCM there is a regulator which provides 16 volts for the Vacuum Fluorescence (VF) displays of the DIC, FDP, and ECC. This regulator also provides the variable voltage input to the ECC power module for blower speed control.
To diagnose and repair these conditions use the following trouble tree.
Tuesday, October 28th, 2008 AT 9:56 AM