Car Stereos: jvc stereo wont turn on when car starts, wire harness, grandam

Question
I have an 04 grandam with a jvc stereo in it. I
also installed new speakers and I have subs. Last
winter my car had a hard time starting and when
it finally did start my stereo would not turn on.  
It only happened a couple times and I got my
battery checked, everything was fine and it
stopped doing it so I forgot about it. I got my car
inspected and it sat in the lot for 4 or so days
while I was on vacation. My car had trouble
starting and once again the stereo shut off. Then
my stereo would come on when I began to turn
the key but as soon as I turned it to start the
stereo would shut off. When I turned the car off
it would come back on (cause my car keeps the
stereo on for 10 minutes unless door is opened).
It also turned on if I turned the key to accesories
or on.  It only shut off if my car started. Now all
of the sudden it won't turn on at all. I'm not sure
what to make of it. Can you help me please.

Answer
It sounds like one of two problems.  First, it sounds like there is a slow draw on your battery all the time, causing it to lose power over time and make the car hard to start.  I don't know what would be causing this, but the stereo might be the culprit.  Second, the radio is not turning on, because the wire harness that keeps the radio on for ten minutes is defective or the radio is not getting 12 volts, because the battery is wore down too far.  If I had to guess about the whole thing, I would say the wire harness that keeps the radio on after key is off, is malfunctioning and needs to be replaced.  Hope this helps, Scott