Can this be done and how? I bought Zumo 660 direct from Garmin to use on my 03RKC, but purchased 09SEUC and was never installed on RKC. Wondering if it is possible to connect audio out wire of Garmin so voice commands are heard thru radio. I don't see any place on back of radio to plug into. Is there a HD pigtail that I need? Local stealer was clueless told me to call Garmin, which I did and was told by service rep that person doing install should know which wires from the Harley radio to hard splice the garmin harness wires into. I said I did not think that was an acceptable wiring solution for such an expensive GPS. Thats all he could offer as a fix. If it can't be made to work I'm ok with that I'll just turn up the built in zumo speaker. Thanks for your help. If there is a post about the wiring I could not find it.
**Factory radio was just replaced last Friday with re-fab unit,so don't really want to go the Iron Cross route just yet.
UPDATE**8/19/10 Zumo 660 installed on dash pad. Took a short test ride and I can hear the GPS voice commands from the unit pretty good. I will just have to lower volumn of XM. All is good for now. Thanks to all who posted!