Audio Systems: Car Speakers, pioneer cd player, nissan altima

Question
I have a '93 Nissan Altima with aftermarket pioneer cd player and speakers which have worked fine since I installed them in February. Recently I have had a problem in which the stereo will come on and play for about 10-15 seconds and at that point all four speakers cut out. Would a wiring problem with one speaker cause this or is a central problem? And how would this kind of thing just come about?

Thanks,

Josh

Answer
a "shorted out" speaker could cause the cd player to turn off. But one speaker shorted out would mean that this speaker wouldn't produce any sound. so for your 10-15 seconds you'd get sound out of 3 speakers instead of 4.  is this happening?  
The Nissan Altima had an option for a BOSE (BLOWS) system.  If you had this then there is probably an amp hidden somewhere thats going bad. Does your cd player continue to appear to be working but the sound just stops?  If so it's most likely this blows amp (sorry I hate bose) Your best bet is to bypass the amp by running new wires from the speakers to the cd player, this will bypass all the factory wireing that goes who knows where to who knows what.  not the easiest fix but it's free and it means there's nothing wrong with your stuff you bought!
If you need help doing this please feel free to ask.