maybe someone else has had this problem & has found what it was? i live in minnesota & during the winter (or when the temperature happens to be below about 30 degrees), after starting the car, there will not be any sound from the radio/cd/tape, but the navi voice can be heard. it seems that this only happens when i start the car for the first time in the morning & then after that, if the car is still warm (hasn't been sitting in the parking lot at work or wherever), there is no problem. if the car has sat for long enough, and its cold enough, this happens several times a day. i've also found that if i turn the ignition off and then restart it sometimes the sound will come back on. i haven't had this happen during the spring/summer/fall at any time, so that is why i am thinking it is a temperature issue.