XM Radio Hummmmmmmmmmmm

This is a known problem. Here's probably what's going on:

http://priuschat.com/forums/toyota-prius-service-bulletins-tsbs/46700-noise-aux-port-06-08-a.html

Hope you can fix it. Many devices which are powered by the car 12 volts and using the aux input seem to be affected. Devices powered by their own internal batteries don't have the noise.

 

I had the same problem until I turned both the bass/treble completely down to the minimum. Walaaaa no more buzz!

 

I have an 08 prius and I had the same problem when i connect my roady xt audio out to the prius aux input. Basically, I bought this item: PAC SNI-1 - Ground loop isolator to install into my car, but what i found out is that either the left or right channel was not working at all because the one of the transformers inside the device was bad. i removed both transformers from the circuit board and used some 600 ohm transformers (200-10k HZ) instead of trying to find a direct original spec type rated for music. I also must say that I had these transformers on hand already; just grabbed a few used ones in the electronics recycle bin at work. they're labeled as TF5RX17ZZ. another one that should be the same as what I used is LM-NP-1001-B1. They don't cost much and are well made in contruction. They're not rated for low frequency sounds such as DEEP Bass, but they do excellent for those that are not even 'picky' with those lower frequencies. Unless you're some sound system bass junkie, these transformers should do fine.

with my application, I ripped out the circuit board from the original PAC SNI-1 unit and placed it in a hobby box i bought from radio shack, integrated dual swichable hard inputs with one of them overided by plugging in another source cable. so basically, my setup is switchable between a constantly connected xm roady xt and my sansa fuze. if my wife wanted to listen to her mp3 music or the audio coming from her netbook or portable dvd player, she would only need to connect the cable into an unused port that overrides the audio line for my sansa fuze with the switched set to source select from my sansa fuze. i don't have pictures or schematics for my build. it's all in my head. i did place the final product in that small space that is forward of the main arm rest storage area just above the aux in jack. no problems with it at all.

 

Go over to Amazon, they have several versions, about $10 bucks.
Nice part is, if it's bad, you can return it, and get a replacement!

http://www.amazon.com/GROUND-LOOP-ISOLATOR-3-5-APPLICATIONS/dp/B001EAQTRI

 

For those who are within the 36,000 Mile / 36 month warranty period, call toyota:
1-800-331-4331 and get this problem fixed for your car. this is the TSB# for those with the 06-08 prius T-SB-0067-08.

Even though I remedied my own problem after buying my used 08 prius, I still want them to fix their problem. I called the 800 number to register my car's problem and found out that my car was originally purchased on 8 Apr 2008. my car's getting close to that 36 month expiration. I also found out that the gas pedal / floor mat issue was not corrected and/or documented with toyota BEFORE I bought my used prius. Shame on the dealership...and i bought my car after that whole issue about this last year. shame on you Roundtree Moore Toyota! Anyways, I bought Weathertech rubber mats.