Cluster not working

[96LT1355Z28]

So when I switched to Holley EFI I left the stock PCM in the car so the gauge cluster would still work (except the tach). At the last LTX Shootout I removed the PCM to let someone use it and to my surprise all my gauges except the speedo still worked. This year I removed the remaining PCM connectors to clean up the engine bay and removed some of the wires and relays in the under hood fuse/relay box. Well now my gauges don't work. All my fuses are good, car runs fine, cluster back lights work and check gauges light illuminates but no life in the gauge needles. Looking at diagrams I can't find where I would have cut the wrong wires but obviously I did something! Any advise?

[96LT1355Z28]

*UPDATE* It was a ground for the cluster itself I had accidentally cut when removing several wires from the sealed firewall connector near the master cylinder. So FYI the oil, fuel, coolant temp and volt gauges will work without the PCM in the car as long as the cluster has power and ground.

[Injuneer]

Correct.... only the tach and speedo are driven by the PCM.