This is labeled as the EFI Main Relay Switched Power in the diagram above, and will supply the VPC with direct power with the key set to the “ON” position.
Now with your VPC installed, you must mount and run the harnesses for the extra sensors required to operate the VPC. Now all that’s left is setting up and tuning your HKS VPC, which we covered in How to Tune your VPC article found here.