I have an 05 Cooper S in which I have installed the Euro Parcel Shelf with a power socket, which is wired using add a circuit to the fuse box. My Roady XT (about 18 months old) sits in the shelf, and is plugged into that socket. The aux input is also installed in the shelf, and the Roady connects to the radio through the aux input (and a ground loop interrupt). I just acquired the Nuvi 360, and when the Nuvi is on, and plugged into the power socket at the bottom of the downtubes, I lose XM reception (the Roady is still on, but no sound comes from the radio). If I use the Nuvi on battery power, the XM reception remains. The two power sockets are on different circuits. Any ideas as to why this occurs and how this situation can be resolved (other than always using the Nuvi with battery power)?