My E9X Dynavin loses its settings every time I turn it off!

Unlike most cars the E90/92/93 BMW 3 series does not have a constant power "memory" wire in the factory radio plug.  Dynavin provides a power wire in the new wire harness that is to be run to the car's positive battery terminal.  This wire MUST be connected for the Dynavin to operate.  While it may seem attractive to try to connect to a constant power source in the fuse box it is not recommended.  Most of the circuits in the fuse box shut down after 20 minutes.  Running to the power wire to the battery is the least time consuming and most foolproof.