Not trying to hi-jack the thread but, this weekend I tested my block mounted lift pump, I pulled it off the truck and jumper wired it to check pressure, the pump has a red and black wire fromthe pump side connector. I thought the black was ground, black from the engine side of the connector is ground, ran the pump and no pressure, reversed the wires and BAM 26 psi. I purchased the truck used and don't know the history but the pump wiring is reversed and could never have put out any pressure/fuel. So black is positive and red is negative on this block pump.