Mercury - Solenoid Switch Relay Down Trim System Component Marine-Grade Construction 898103T10. Overview. If you run a jet outboard or a high-horsepower Verado, you know how much you depend on the trim system to respond the moment you touch the switch. When the relay is healthy, trimming the engine down feels immediate - a smooth, steady drop that settles the boat and gets you ready to accelerate, maneuver, or push through chop. The Quicksilver 898103T10 Solenoid Switch Relay Down restores that