4 Plug Wiring Diagram - Hopkins Wiring - 47515. Trailer wiring adapter that changes the 4-pole flat on your vehicle into a 5-pole flat. The blue wire gets spliced into the reverse light wire on the vehicle which is easily done with the included quick splice wire connector.. Welcome. The wiring diagrams below come from 1) original owners manuals, 2) service manuals, 3) supplement sheets, 4) parts manuals, 5) actual mopeds, wirings, or parts, new or used, or most often 6) a combination of most of those.. Pinout of USB and layout of 4 pin USB A or USB B plug connector and 4 pin USB A / USB B / mini-USB jack connectorUSB (Universal Serial Bus) designed to connect peripherals such as mice, keyboards, scanners, digital cameras, printers, hard disks, and networking components to PC. It has become the standard connection method for wide variety of devices..