There is a grey wire loom with a white Molex plug that ships with all the Air-Engines.The wires inside of this plug have two different colored wires then the wires that are actually wired to the Air-Engine. The table below shows these differences in wires and which one goes to which. The (WL) represents the color of wire that will be coming out of the grey wire loom and the(AE) represents which wire actually goes into the Air Engine. The loose red/pink wire that doesn'trun inside the loom isn't used and can be cut off.Exact measurement of any position of the 4 sensors & tank air pressure.The air pressure gauge will read and operate correctly between range of 0-20bar (Max 300psi)●User adjustable High & Low air pressure warning pressure setting.