Rev counter connections

[qual996]

Please can someone advise on the connections for the electronic rev counter.
The wiring diagrams are somewhat unhelpful in showing the actual connections on the base of the instrument.

The loom has four connecting wires, one brown, one blue, one grey and one yellow/green.

The rev counter base has a yellow wire protruding and then three connection points :- one marked +, one marked earth and the third one is marked with the number one,1.

Can you tell me what connects to what please

Thanks

John

[EVguru]

Brown is a positive feed (switched).

Blue is a ground.

Grey is connected to one of the ignition modules.

Green/yellow is lighting.