Audio Systems: Car Stereo Squeals...., inline fuse, suzuki swift

Question
Hi Cody...
         I've just installed a secondhand Pioneer DEH-P3150 in my girlfriends 1992 Suzuki Swift.  All seems to be installed right, but on both cd and radio as soon as I turn up the volume the speakers start to squeal.  It's certainly not cranking before it does this.  The only thing I can think of (I have not yet tried this) is that maybe the inline fuse I used is not powerful enough?   Either that or the unit is somehow faulty.
I'm not sure what rating fuse I used as I used the same one that was on the factory stereo.
Any suggestions would be greatly appreciated.

Regards
Christian  

Answer
Christian,

 the fuse shouldnt give the problem if the fuse wasnt high enough amp it would simply blow, it sounds to me like the unit has a short somewhere internally, but to knock it out for sure take a speaker you know works even a home speaker will work for the test, and pull the unit out and unhook the speaker connections and wire one channel say left front to the test speaker to see if the same problem occurs, if it does toss the unit .. if it doesnt re-run all new wires to your speakers and hopefully that should cure it .. hope this helps you out if you need anything else let me know

thanks