I am sure most of you have already experienced this by now.  When i get into my hot sweltering car the Avic overheats and the ATT function turns on which lowers the music to a mute and stays on.  From my previous pioneer headunits I know the problem is simply because of overheating and not a wiring issue.  Behind my headunit there is not much room and the only way I can get rid of this is by putting on the AC and closing all vents so the air can cool down my radio and regain my volume.  Any of you guys either put a fan behind the headunit to help cool the unit down the hot summer days?

Which head unit? 

Z150bh

Z150bh

Did you do the parking brake bypass, or did you run the mute wire to the adapter?

Did you do the parking brake bypass, or did you run the mute wire to the adapter?

I did the parking bypass and I may have connected the mute wire ill check today assuming it is connected I will disconnect the mute wire

Still doesn't explain why I have to turn my ac unit on to make it stop

Had the exact same problem as you're describing. However, in my case, I found out it wasn't the radio overheating....it was the Metra Onstar interface that was overheating causing it to send random mute signals to the mute wire of the Z150. Got my Metra interface replaced and moved it to a more open place inside the dash, haven't had a single problem since.

Had the exact same problem as you're describing. However, in my case, I found out it wasn't the radio overheating....it was the Metra Onstar interface that was overheating causing it to send random mute signals to the mute wire of the Z150. Got my Metra interface replaced and moved it to a more open place inside the dash, haven't had a single problem since.

That's what I found to be the case. I cut the wire from the Metra unit and life is good. I can still hit the mute button on the steering wheel and the unit will mute.

Douger is right, I had the same problem with my Avic-Z130 when I first got it. After trying a bunch of different stuff, it turned out that it is the metra adapter sending the mute signal to the unit. I cut the yellow/black mute wire from the headunit and its been working great ever since.