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There are 4 wires from the relay.
1) + from battery
2) Trigger for relay; tapped into stock fuel pump wire (activated with key "on")
3) + to Fuel pump - soldered the (3) to a stock pigtail lead
4) Ground to chassis ground - at seat-back anchor bolt
You may have wondered how I was getting alternator-level reading with my volt meter while holding the power plug in my hand - how was the engine running? Well, I essentially have a redundant solution as far as pump power goes. I retained my stock harness and plug because I didn't want to hack it up. I also bought an extra pigtail off an IS300 salvaged car that I wired to my upgraded fuel pump wiring. I then simply depinned the fuel sensor / level wires from the stock plug and pinned them into my "new" plug. This results in me having a fully pinned plug for my heavy gauge wire lead. But in the event I have a problem with my solution and blow a fuse, etc., I retain the original plug and power (albeit without the fuel level wires connected) to limp home. So to get that picture, I was driving the pump with the stock wiring & plug, and metering the power coming from the battery & relay via the upgraded wiring to the "new" plug.
Crude wiring diagram Grey is upgraded plug / wiring pigtail. White is the stock plug / wiring retaining only the stock + and - fuel pump wires. Overview with grounding location in lower right corner 4 relay wires - red = +, black = -, blue = trigger Wiring overview
