HI Daniel, need more information mate
When was the last time they were working and what work has been done just prior to the lamps coming on?
Does your car start/run, and does other things like tacho, fuel gauge, speedo work (strange question I know)
Assuming it runs
Did you pull, check and re-seat each fuse (in cabin) ? Just confirming. Especially the ones marked "Electrical Parts", and "Engine Control"
What's the health of your Battery ?
Lights mentioned above have an affinity to the Ignition (IGN) relay. answer to your question above. If it was blown then your car wouldn't start.
From the small amount of information given it could be a number of things
- Not grounded properly. Check all grounding wires/points in your Skyline
- Connector/s plug in the harness not secured properly
- Wiring harness damaged that carries all three signals
(as you have replaced the cluster with a known working one - cluster ruled out)