98 Eclispe Radio Install

Sounds like you've got a factory amp.  Look under the passenger seat.  You can bypass it there, or run new wires to the speakers.  If it's the seven speaker system, it's best to upgrade the speakers at the same time, since the factory amp does all the crossing over of frequencies (no caps on the tweeters).  I usually just disconnect the center channel.My ex once told me I have a perfect face for radio.

I didn't see an amp under the passenger seat.  Can it be in another location?  Which cable should I follow to get to it?

Do you have a seven speaker system?  If not, there's no amp.  You didn't cut the harness off did you?  You should use a Metra harness to hook it up and you'd be done.  Does it look like this?  http://www.installdr.com/Harnesses/Mitsubishi-Wiring.pdfMy ex once told me I have a perfect face for radio.