I had my XM MiFi installed at Best Buy. I have it plugged into the AUX jack (2006 Prius). At first they used a standard, generic "mini" to "mini" cord to hook up th device. It worked, but there was a terrible hum in the background. They swapped out the cale and replaced it with expensive Monster cable "mini" to "mini". The overall qual;ity of sound is great, but there is still the annoying hum. Anybody had this problem? Is it a grounding issue, do I nedd some kind of noise filter...HELP? I love XM Radio!!!
The noise is coming from the power adapter. Unplug from the AUX jack and the noise will go completely away. I had the same problem, but I solved it by installing Coastal's XM radio kit into the car and selling the MiFi. Hopefully, someone else has solved the problem. ---Kent