Help Difference between analogue cluster wiring and digital

[coggs]

Trying to fix a few things on a secondhand transit mk6 2.4 2001 125ps ... engine running but low on power ... Speedo is analogue but no temp gauge or glow light checked wiring all there ...Only error code is IAT sensors but my wiring loom has a Ford Fitted blank on that sensor cable ..... ECU fitted is 3C11-12A650-GA which I believe is a digital cluster part number .
anyone help as I don't know where to start.