Mercury - 3-Pin Extension Harness (10 ft) Rigging Accessory 84-8M0191744. OverviewThis 10-foot extension harness gives you the extra reach needed to connect the steering 3-pin lead from the rig center breakout to the electric steering actuator. It's meant for setups where the shorter harness won't quite make the run or where a cleaner, gentler routing path is needed. Each actuator uses its own harness, which keeps the wiring relaxed and helps the steering system respond the way it should.. Key F