I had a problem last summer with the sound cutting off when it was real hot. Real hot as in the sun beating on my black suburban in 90 degree heat all day. I turned on my CDA9813, drove away and in a minute or so no sound. If I turned the unit off then on again, I had sound. I'm sure it's just the internal protection shutting down the unit to prevent damage. I just realized last week that I had the internal amp set to ON in the setup. I don't need it because I have external amps. So my question is, now that the internal amp is set to OFF, is it still technically on but just not providing output, or is it really turned off - as in not generating any of its own heat?