Hi all lets cast our minds back to when I was playing with my clocks so that the speedo worked and the odometer worked etc....update time everything works but instead of a red or yellow light when running low on fuel lets sustitute a cough and a splutter and a short wheel spin as fuel found its way to the injectors every now and then....fortunately I rolled into a Caltex servo at Penrith and filled her up and I now know that my tank does hold 21 litres.
Ok that was fun and exciting but how to troubleshoot the fault given that the only change was the replacement newer model clocks to which I transferred the old PCB for the fuel lights which attaches to the Tacho assembly.

Or I just get better at guessing how far to go on a tank full....wish it had a reserve switch...now I also have a speedo which is as pessimistic as modern vehicles about 5 km's out...shame as the old one  (when it worked) was spot on....

I assume you have used the conductive film from the new cluster, then we can leave
the 7L circuit out as the connectors isn't present at this conductive film.

Then we have the 4L circuit left.....and all did function OK before changing the pcb...
I would guess a bad connection in one of the connectors between the conductive film
and the pcb.

In the new cluster.....(the obvious    ) is the bulb present, and function checked?

Possible that the PCB folded under itself and is not making contact with the bulb.  Or, could the bulb be burned out?

there is a pot in the speedo assembly that can be adjusted klompy

that kurumba software is ideal for doing the adjustment ...whilst you have the instruments undone