Please post a picture of the non-working display.

Just for clarity. Is it the original display or a newer display from Pinscore, or elsewhere?

https://pinside.com/pinball/forum/topic/taxi-shows-jackpot-value-all-the-time

I found this on some old guides I dug up. Looks like it may be worth checking out R62-R68 on the display board.

"Taxi and Police Force use a slightly different style of display board. Both these games use the two 16 digit alphanumeric score display, but also have an extra third 7-digit numeric score display. In order to accommodate this, the standard system11 alpha-numeric display board was modified slightly and a second ribbon cable connector was added to the board.

Taxi and Police Force have an alpha-numeric display at the top in the backbox, and an alpha-numeric display below it in the backbox which is only used for numerics. Diabled on the bottom 16-digit has the following disabled: right side hash mark, some commas and periods. These item are removed from the bottom 16-digit display so the circuitry could be used to drive the additional 7-digit numeric display. The bottom 16 digit display on these games only uses 8 segments (the middle segment of the display is used to make the number zero into an eight, which is two segments). This leaves six segments and the "comma" left unused. The unused segments are then used to drive the extra display. This is the reason there's a second place to hook up a ribbon cable on the Taxi/Police Force display boards.

The Taxi/Police Force style display board can be converted to work in the other 16 digit alpha-numeric system 11 games, with a small modification. Simply install the missing seven resistors into locations R62 to R68 on the Taxi/Police Force display board.

Likewise if a display from a BK2000 was used in a Taxi, a few things have to be added: U3 (UDN6118) and resistors R9-R13 and R15-R18 (all 10K resistors) Also remove R67, R65, R64, R62, R60, R57, R56, and R54.

Banzai run also uses a unique display board. The Master display board is the same as pre-Taxi games, but the display board itself is unique. It is a single sided board and often has delaminated board traces. Remember Banzai uses two 7 digit alpha-numeric displays and two 7 digit numeric displays."