I doubt the xm antenna will work under the dash, but you could always give it a try. I like the idea of trying to retrofit pioneer's antenna into the stock gm xm antenna plastic somehow. Otherwise just run the wire above your headliner and run your wire through the edge between the metal and plastic on the the top of the third brake light. How exactly did you hook up your dimmer wire, mine didn't work directly off of the adapter so I installed a switch under the dash for now. I just purchased the "ducati" circuit so any info to make it work with the headlights would be appreciated.
