Audio Systems: 98 expedition radio, premium sound system, stock radio

Question
i haqve a 98 expedition recentialy i changed th srock radio so i got the wiring clip from a audio shop wired it up everything works but i get no sound from the speakers so i put the stock deck back in and it works fine can you help me

Answer
the 98 ford expedition was available with a premium sound system.  if your car has this, then there is an amplifier hidden in the car somewhere.  this amp needs to be triggered to turn on when you turn the cd player on.  if you look at page 8 here they talk about it for your vehicle:

http://www.installdr.com/InstallDocs/FLM/PDF/356033.pdf

most likely there is a wire on that wiring harness that either isnt in use, or there's a wire going from the car into that harness but doesnt continue on through the harness you bought.  this may be the trigger.  do you have a meter that you can test this wire and see if it gets posative voltage when you turn the stock radio on?  If you dont, you can get one for about 18 bucks at radioshack or walmart or homedepot or any auto shop.  if you need help in using it, let me know I'll be happy to help. but I think this is what you're missing.

Let me know.