Car Stereos: Power but No Sound...Help, jeep cherokee country, alpine speakers

Question
I have recently upgraded my car sound system. I purchased a
Pioneer Premier DEH-P400UB, 4 Alpine Speakers, 2 Bazooka
10" Subs, all hooked up to a Boss D1800 1800 Watt 5 Channel
Amplifier. I let a store around me with a good rep. install
it. I picked it up, and everything was just fine, it all
worked properly. I was driving it home and it just cut out.
Everything was powered and my head unit was saying it was
playing but no sound came from either my speakers nor my
subs. I got home and checked my amp, it was hot. I figured
I would just let it cool. After a little while I turned it
on and everything was fine again, I could turn everything
up loud with no problems. The next day again everything was
fine. I don't drive for long periods of time, but after I
dropped off a friend it cut out
again. I thought that it was hot again. I checked it, and
it was warm not too hot, but let it cool anyway. 2 hours
later I came outside and no sound again, the amp was cool,
and there was still no sound even though my head unit said
it was playing. I took it to a friend who knows a little
something about car audio and he took a look at it. The
fuses were good, the wiring was good, everything seemed to
be hooked up fine, but still no sound. About an hour of
fussing about trying to find out what it could be we turned
it on and sure enough we got sound. I turned it up and it
cut out. We knew it had to be the amp, but what I was
wondering is if it is something else. Maybe the amp is
getting too hot, or the amp has some kind of technical
problem and I need to send it in. What do you think it
could be and what should I do. The place that installed is
not open on Sun or Mon so I cant take it to them.

I have a 1993 Jeep Cherokee Country

Answer
Hi Chris,

The amp is overheating, and the cutting out is a thermal cut off it's doing to protect itself.  If it's overheating a lot, either it's being driven too hard (turned up too loud), the speakers hooked up to it are shot (not likely), or installed incorrectly (too little resistance across the circuit), or the amplifier is mounted somewhere in a way that it can't dissipate heat effectively.  If you're not overpowering it, and the speakers are hooked up correctly, you might just have a busted amp.  Either way, the shop that did the install is going to have to look at it and give you their recommendation and/or replace the amp to fix it up.

Justin