Originally Posted by iissmart

Did some more testing at lunch today. FM radio sounds good, satellite radio sounds muffled, and my aux port has tons of noise/hissing. I'm using a blackberry bluetooth adapter which is powered from the 12v socket in the center console. Is this normal? It sounds clear when the car is off, or when plugged into my phone (and not charging). But there is a massive ground loop hum coming from the 12v socket while the engine is running.