Digital fuel display not working - 1992 Cadillac DeVille

Did you test before replacing ? Do you know how it work's ?

Fuel Level
The body control module (PZM) monitors the fuel level sender input in order to determine the current fuel level. The PZM filters the input and sends a message via the Class 2 serial data line. The IPC receives this message and displays the current fuel level. The fuel level is sent from the PZM to the IPC at changes of 0.5 L (0.02 gal) or on the request of the IPC, with a resolution of 0.04 L (0.01 gal).
• For the digital IPC, when the fuel level is above 18.5 gal, the IPC displays an F. For readings between 18.5-2.5 gal, whole gallon/liter numbers are displayed. When the fuel level reaches 3.0 gal the message FUEL LEVEL LOW is displayed on the driver message center. When the fuel level reaches 2.5 gal, the IPC displays an E. When the fuel level is 1.2 gal or below the IPC displays a flashing E.
• For the analog IPC, when the fuel level is above 18.5 gal, the fuel gauge pointer is on F. When the fuel level is below 2.5 gal the fuel gauge pointer moves to E. When the fuel level is below 3.0 gal the IPC displays a FUEL LEVEL LOW message.
If the updates are not received or a communication error is detected, the IPC performs the following actions:
• For the digital IPC, the fuel gauge is dashed.
• For the analog IPC, the fuel gauge pointer moves to E.

Fuel Gage Inaccurate or Inoperative
Circuit Description
The IPC monitors the fuel level sent by the PZM through the class 2 serial data line. The IPC software controls one of the following two gauge types:
• A digital gauge consisting if a two-digit numeric seven-segment display
• An analog gauge consisting of a needle pointer.
The IPC interpolates and scales the fuel level information that the IPC receives from the PZM.
When you operate the vehicle in diagnostic mode, either in the vehicle diagnostic system or with a scan tool connected, the fuel signal supplied to the IPC is not filtered by the PZM. The unfiltered fuel signal causes the IPC to show real time readings and may be mistaken as an erratic fuel level display.
Diagnostic Aids
Connect a scan tool to the DLC.

Perhaps you failed to hookup supply wire or broke a fusible link.

first I would check to make sure the computer is hooked up properly if so then it may not be any good.

what could be the problem ???? The problem is you tried to fix something you have no clue how it works .... Your best bet , take it to a qualified repair shop. You have no idea of the complexity of these cadillac systems . I know you don't have a $ 5000 dollar factory scan tool or equivalent to diagnose . The sending unit in the fuel tank is a input to the BCM . The BCM sends this info to the instrument cluster over the class 2 serial data network - communication network for the control modules on the vehicle. Fuel Level
The body control module (PZM) monitors the fuel level sender input in order to determine the current fuel level. The PZM filters the input and sends a message via the Class 2 serial data line. The IPC receives this message and displays the current fuel level. The fuel level is sent from the PZM to the IPC at changes of 0.5 L (0.02 gal) or on the request of the IPC, with a resolution of 0.04 L (0.01 gal).
• For the digital IPC, when the fuel level is above 18.5 gal, the IPC displays an F. For readings between 18.5-2.5 gal, whole gallon/liter numbers are displayed. When the fuel level reaches 3.0 gal the message FUEL LEVEL LOW is displayed on the driver message center. When the fuel level reaches 2.5 gal, the IPC displays an E. When the fuel level is 1.2 gal or below the IPC displays a flashing E.
• For the analog IPC, when the fuel level is above 18.5 gal, the fuel gauge pointer is on F. When the fuel level is below 2.5 gal the fuel gauge pointer moves to E. When the fuel level is below 3.0 gal the IPC displays a FUEL LEVEL LOW message.
If the updates are not received or a communication error is detected, the IPC performs the following actions:
• For the digital IPC, the fuel gauge is dashed.
• For the analog IPC, the fuel gauge pointer moves to E.

Fuel Gage Inaccurate or Inoperative
Circuit Description
The IPC monitors the fuel level sent by the PZM through the class 2 serial data line. The IPC software controls one of the following two gauge types:
• A digital gauge consisting if a two-digit numeric seven-segment display
• An analog gauge consisting of a needle pointer.
The IPC interpolates and scales the fuel level information that the IPC receives from the PZM.
When you operate the vehicle in diagnostic mode, either in the vehicle diagnostic system or with a scan tool connected, the fuel signal supplied to the IPC is not filtered by the PZM. The unfiltered fuel signal causes the IPC to show real time readings and may be mistaken as an erratic fuel level display.
Diagnostic Aids
Connect a scan tool to the DLC.
Test for any set DTCs if no DTCs are set current. Refer to System Check in Body Control Module (PZM) Diagnosis.

Your best bet , take your vehicle to a qualified repair shop.

Hello: This could be the fuel level sensor is not connected or the sensor assembly was damaged or bent when assembly was reinstalled or the fuel pump was not installed on the sending unit correctly.

Those instrument clusters are LCD Liquid crystal display, and once they no longer work you need to get it replaced.

Change fuel filter and pump or fill car to full Ac Hot Disabled is a Dummy code The problem is low Fuel pressure

ive got a 55 plate 85 T260 swb crewcab 68000 miles, , i bought it 12 months ago, red light flashes on dash board most days, some times arratically, sometimes quite slow, and all clocks, speedo and dash does not work?????????
the smallest scratch and the van rusts, no under seal, there just a use it and dump it van.

i would just like to say fords are ****

this is caused by a circuit board failure inside the digital cluster, this cluster can be rebuilt, the only real option on these is a factory repair center, contact your GM dealer for a name and number.

The digital display is controlled by a processor board, and yes the board goes bad, but fixing it, well I have tried many times with no sucess, I always in the end got a rebuilt cluster from GM.