Car Stereos: car stereo not working, jvc car stereo, factory stereo

Question
i have a 2001 ford explorer and am trying to take out the old stereo and put in a new jvc car stereo, i cut the wires and put them together with the wires that come with the jvc matching speaker and power wires but all the stereo does when i start the truck up is nothing unless i press eject then the screen will light up and say do disc then it will turn off again,any suggestions,do i need a wire harrness or can i simply just cut the wires and match up the wires there are more wires that go to the factory stereo that i never connect to the new jvc,any ideas?

Answer
Ian, how do you know what color wires are for what speakers?  How do you know any of the wire colors?  A wire harness adapter tells you what each of the wires is for, so you connect them properly.  Without the adapter, you need a wiring diagram of your cars wire harness to determine what each colored wire is for.  My guess is that there is at least one wire that isnt connected to the proper wire.  Hope this helps, Scott