I just want to clarify some important details with the extra break-out wires that is connected to my harness. The red one on the right side (A-unit side) is an optional wire that can be connected to a 12 volt source, but it must be a fused one. This is to feed the instrument cluster with power when your car is turned off, so to keep the clock working together with the KMH/MPH setting, and dimming setting. Note that this is not required for the cluster to work. If this wire is not connected, each S2K cluster will default it's KMH/MPH setting to it's region, meaning that clusters pulled from vehicles sold in the US will default to MPH. (On some clusters, like the EDM/JDM AP1, this button is disabled, but I can enable it via software at the same time as I reprogram the odometer).
One simple alternative is to make a T-connection to the white/yellow (WHT/YEL) wire that goes to the NSX clock in your dashboard (see page 23-224 in 1991 NSX Service Manual or page 23-233 in the 1997-2005 NSX Service Manual), this is what I did. Note that the color coding for your vehicle year might be different. Simple to measure though, should be 12 volt when the car is turned off with key out. The other alternative, which I haven't explored, is to crimp a spade connector and run this into an unused (fused) source in any of the fuse boxes. NEVER EVER connect any wires directly to the battery without a fuse. Cars have burned down for less. Safety is important.
The black/red/green ones on the left side (B-unit side) are ground (GND), switched +12 volt and the oil pressure signal, respectively. The ground and 12 volt wires as meant to power an external voltage meter and an external oil pressure meter. Meant only for low-current applications, not like audio head units or similar which are high-current applications. The oil pressure signals connects directly to an oil pressure meter to provide the signal from the cars oil pressure sensor. All of these three wires are also optional and not required for the cluster to work.
Best regards,