So for the past year that I've owned my G37 I have randomly had issues with the factory bose system. Issue is no sound, but here is the weird thing about it. This issue is almost non-existent during dry summer days, but if its raining or cold out then it happens. So what happens is I start up the car on one of those "bad times" and theres no audio at all, but if I am driving for about 15-30 mins straight, then the audio will come up all of a sudden. It also seems to help if I drive fast.I've noticed usually if I hit 80Mph or faster, then the audio will kick in. By the way, once the audio is working I wont have any issues until I turn off the car. Now again, the odd thing is this only happens with random weather changes like a cold front comes through or if its raining out. During the spring and summer its pretty dry in my area, so the issue I thought had gone away, but now that were fall/winter it came back again. What I am suspecting is that some moisture gets into the amp during those times it stops working until certain circuits in there warm up enough to dry out the moisture. Something to mention is that my car came without the rear inner tire covers. So that being said, there is a factory air flap in the rear tire well that leads to the area by where the Bose amp is located, so that is part of the reason I think maybe thats it, but at the same time it doesnt make enough sense to me with the car parked how enough moisture can get through there. Another note is that I can wash the car and have no issues. It just needs to be exposed to the rain long enough.
Anyone have any ideas or thoughts what this issue might be?
Thanks in advance

 

Check the drain holes around the trunk under the black plastic

 

Thanks for the response Surfnazi, Im not sure where those drain holes are at, but here's a pic of the area by the amp after removing the black plastic cover, and the circled area is the vent that I was referring to that maybe is letting in moisture. The area isnt wet or damp, so maybe its not that, or the amp is just that extremely sensitive I dont know.

 

Thats vent for gas the drain holes are on top part of.the trunk where it connects there is plastic trim that goes down to the brake lights look under that

 

It's been a long time since I had this issue and finally got it resolved. Just wanted to share what it was incase anyone else encounters it. So randomly on cold days or rainy the audio system wouldn't produce any sound until about 20 mins into the drive. Head unit was displaying like it was functioning, but just not getting any audio from any speaker. I replaced the larger main bose amp with a used one of eBay, and since then I have no longer had the issue. I wanna say somehow the weather was affecting the amp maybe from the solder points or not sure, but replacing it fixed my issue.