Installing a Rev Limit Shift Light .

[Sindako]

Hello Mates .
see i was wondering .
i saw this product and i want to install it on my e30 .
but how would i do that ?
i need to know which wires on the harness or tacho sensor should i be connecting to give it a read so it can light up when i reach my Rev limit .

See it has an adjustable rpm level so it can turn on when rev reaches it's limit depending on car and rev level .

http://www.ebay.com/itm/ADJUSTABLE-RPM-TACHO-TACHOMETER-BLACK-ALUMINUM-TUBE-RED-SHIFT-LIGHT-4-6-8-CYL-/400708953480?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item5d4c1d6588

that's the light i want to install .

Please Advise me what wires give reading to the cluster , or a way to install it properly and let it work properly .

it has a 12+ , GND & signal , i know the GND and 12+ are easy to find anywhere on plug/accessory box , but where do i plug to connect signal to ?

Cheers

[Gregs///M]

Engine speed out (from ECU) is black wire in the blue harness behind cluster.

The black engine speed wire can also be found at the round plug under the hood.