There have to be four connections. They don't all have to be wires.
Power input to the relay
Power output to the pump
signal input from the ECM that powers the electromagnetic relay coil
signal ground from the relay coil
Put another way, power through the relay to the pump
power through the relay to activate the electromagnetic coil.
Wild guess: The ground connection isn't done with a wire, there's some buss-bar or something.
Beyond that, I can't read the diagram well enough to determine wire colors.
|