XM Sirius antenna 2012 with Navigation

I have a 2011 Prius V with navigation and recently purchased an adapter to connect a standard magnetic mount XM antenna instead of using the factory antenna which really is terrible. After reviewing various posts, I found the connection was to the XM receiver located under the driver's seat. Works great. I get reception almost anywhere.
I purchased another adapter to do the same to my wife's 2012 Prius V with navigation and find that the receiver is not under the driver's seat. I wonder if anyone knows where the receiver and point of antenna connection is?
I'm guessing that it may be in the dash, but I found on the 2011 Prius that the connection behind the dash was for the GPS navigation, not the XM.