Garmin Gxm 51, Xm Marine Satellite Weather Receiver. on 2040-parts.com

Not working. This is being sold as a non working item.
There are no signs of damage but I cannot get it to connect to my chartplotter.
Here's a description from Garmin's website..
Delivering U.S. graphical weather data directly to your compatible chartplotter, this sleek, watertight XM satellite receiver/antenna offers easy plug-and-play installation with NMEA 2000 network connectivity. The integrated all-in-one design means there is no remote “black box” to install.
The GXM 51 can be powered directly through the NMEA 2000 bus, so no separate power connection is required. In addition to conventional pole or surface mounting, the GXM 51 can also be installed on the underside of many fiberglass decks, using the included under-deck mount. Access more than 20 different types of weather information (including NEXRAD, lightning, wave heights, water temps and wind data) from your chartplotter screen (depending on the XM WX Satellite Weather package). Plus, with a subscription, you can use the GXM 51 to enjoy more than 170 channels of quality audio via SiriusXM Satellite Radio.