I have bought a speedohealer v4 and universial harness for AP1 cluster swap works for my DB8. There are 4 wires at the speedohealer; red for 12V; black for ground; white for the original harness at the DB8 and green for the AP1 cluster.

Everythings are correct and function but the speedo shows nothing. I have heard that the white wire of the speedohealer should be connected at the signal wire which is near the gearbox.

What should i do, please advise.

Thanks