The devices that power the segments on the LCD displays aer called line drivers. They are Integrated Circuits that are connected to the LCD display in the driver P.C. board.
They are usually 16 pin I.C.'s soldered onto the P.C. board.
Sometimes the solder joints that connect the devices to the board can come loose with vibration, and can be fixed by re-soldering. The worst case is that the device has burned out the transistor driver inside the chip and the line driver must be replaced.
In some cases the flexible ribbon cable that connects the display to the board can be oxidized and that will cause individual segments to dim or go out.
Does it have the same segments on all the numbers out, or does it appear to be random as the numbers change?
Try pulling the display out and reseating the connectors to the flex circuit on the dash. It might bring it back.
