New to the forum. Just installed a sirius sat radio to my 2005.5 A4. Radio does not recognize the unit. All connections are good, unit does have 12V. What am I missing? No instructions, purchased new from Don Rosen Imports. Thanks

 

I think there's a plug that needs to be connected under the glove box. There's a write up for it in Audiworld.com

 

Had the same problem with mine, not enough voltage, I had to take to CarToys and the guy installed a voltage booster on the back of the unit, works fine now. Are you getting power to the unit? Is it a built in unit or portable?

Where did you mount the antenna?