Audio Systems: car stereo problem, stereo speaker system, stereo head unit

Question
Hi. I have a 1998 Ford Expedition Eddie Bauer Edition. It has the fancy Mach-whatever stereo speaker system in it. When i bought it it still had the original stereo system in it. My husband put in a new stereo head unit that had a cd player/radio, etc all in one. It worked great for about 3 years.. then one day it turned on.. and then the sound quit.  I turned the stereo off and back on and it worked just fine. Slowly over a few months it got to where it would only have sound for a few seconds. Then it quit having sound at all. The stereo head unit itself has the little blue light bars that go across showing the sound level or whatever that means..and that was working just fine.. like it SHOULD be playing. Just no sound.  That husband-person is no longer around. I was thinking about buying a new stereo..but if there is something i can fix.. like a fuse in the speaker line that i have no idea about.. or something i can do to fix the one i have.. well.. i would rather do that instead.  Can you help with some specifics on what and where to look? My son is willing to look at it if someone could point him in the direction to look. Thank you for any help you can give!

Answer
Hi Susan.
That systems' speakers have amplifiers built onto them.  My best 'guess' would be that the deck he put in is feeding them speaker level power instead of preamp level power (much less power since it lets the individual amplifiers do the amplifying)which in turn, is making the amplifiers overheat and shutdown.

This may seem like I am blowing you off but this is my best advice in these situations (rest assured I am not):

My best advice when interfacing to stock system components (Speakers included) is to go to http://www.crutchfield.com/app/car/carselector.aspx?lp=%2fApp%2fCar%2foutfitmyca
Then, answer a few questions about your vehicle and the site will only display items which 'fit'.
You do NOT have to purchase from them to see what 'fits' once you complete the questions (2 or 3 depending on the vehicle).
You can also call them at 1.888.955.600 to speak to a real person about this.
They know all about properly interfacing to that system with ease.

Jm