atv4wdwiring 001. This is the 4wd cabling layout with 5 main components. The speedo for a display of the 4WD status, the Switch to toggle from 2wd to 4wd on the right of the handle bar, the actual 4wd mechanism and the 2 relay boxes on the frame which control the 4wd motors. Other than a sensor in the transmission which probably sends a signal to the speedo for display of speed, this circuit is totally independent of the rest of the bike and should not have any bearing on engine performance.