Elevens, just as LIRS6 pointed out you can use the GPS antenna going to the Onstar system since the analog Onstar system is now dead. I was able to pull the carpet back and unthread enough of the cable to get it to stretch up and hook into my RNS-E without having to use and extension. For it to work with the RNS-E it just plugs in, the same type of connection, for a Kenwood or Alpine unit I have no idea. The GPS plug for our cars is known as a Fakra lead. Many of the conversion parts can be found here. http://kufatec.com/