Engine Whine

I just put in a new head unit wih Aux input into my 93 Nissan truck. I also installed a Sirius car kit at the same time so that I can take my plug and play satellite unit into the truck. Everything is installed and the radio sounds great when tuned to an FM station. However, when I switch to the Aux mode to listen to Sirius I am getting some fairly loud background hissing along with engine whine in the speakers as I increase speed. Not sure why I'm getting the noise while listening to Sirius and not FM.

Any thoughts?  

Do you have the Sirius just pluged in to the cig lighter? If so that might be causing the wine and noise. Try getting an add on cig lighter and connect it to the same power and ground as the stereo. Do not cut the Cig power adapter off the power cord for the sirius it has a voltage step down to give it the correct voltage if cut off it could blow the sirius. If this doesn't work check your ground wires for the accessories. Also check and make sure you are using the correct audio out port for the sirius it should say out or have an ear phone symbol. You could also try and turn off the built in FM modulator. Give it a try and let me know what happens.