4runner cd changer placement

Hi,

I just got a factory compatible cd changer for my 99 toyota 4runner; but I haven't installed it because I can't decide where it should go.  Is there a difference in performance depending on whether I mount vertically or horizontally?  Anyway, any info would be much appreciated.  The stereo doesn't sound very good sitting on my kitchen table.

Thanks.

Try under one of the front seats if it'll fit (keeping in mind the seat moves forwards and backwards, and up and down if it's a power seat).  Or all the way in the back flush against the side of the car sometimes works for SUVs(but ONLY if there's something sturdy to mount it to).  Do NOT drill through the side of the car!  Also, most changers require you to mount it within something like 20 degrees of vertical or horizontal (depending on how you have the switch set) so make sure you find a flat vertical or horizontal surface instead of mounting it on a curved wheel hump or something like that.

And of course, as always, double check where you're drilling to make sure you don't go into something important like a gas tank or a fuel line. 

Well, I got the changer installed ok, horizontally underneath the driver's seat.  It worked just fine until...  Suddenly the head unit switched to radio, and wouldn't recognize the cd changer.  I figured the cord was loose, so I replugged the patch cable where it meets the changer.  Voila, problem solved, except that this keeps happening.  So do I have a bad cable, changer, or head unit?  I'm sure the plugs are secure enough; I'm not sure what to try next.  Any advice??

thanks