Boss Mgr350B Wiring Diagram. Boss audio mgr350b user's manual page: Get this manual by email. 2003 polaris trail boss wiring diagram from circuitwiringadam.z21.web.core.windows.net Center • the mgr350b should be wired directly to a vehicles battery • when wiring directly to the vehicles battery, be sure to disconnect the batteries negative terminal wire before starting any. […]