Mine is working fine. It's not as loud as the Ipod using the auxiliary input, but it is as loud as my Zumo 660 MP3 player that uses the auxiliary function. The volume difference is noticible if I dwell on it, but at the end of the day it's not a big enough difference for me to continue to get aggravated over it? I agree, it should play as loud as every other function, but it doesn't. I have the 4" Rinehart system with the performance baffles, my bike is very loud! I can hear my Ipod using the interface at 80MPH enough to be satisfied. It's just as loud as the radio, XM, and my Mp3 player which I won't use anymore. For whatever reason, the Ipod hooked up directly to the auxiliary plug is a little louder? Maybe becasue it's more of a direct connection...not sure. Good luck, it sounds like you may possibly have a bad unit?