cd player, 1993 mercury villager

hey all, got a 1993 Mercury Villager LS for free for a winter beater, my other car is off the road. last night i took out the stock tape deck and put in a sony cd player, i used the proper wiring harness ( http://www.bestkits.com/ViewImage.aspx?img=i/BHA5514.jpg ) the one on the right is the audio, the one in the middle is the power/Gnd and what not, and i have no idea what the one on the left is for, i was thinking maybe it was for the models with an EQ or something, but mine does not have one. Anywhoo i hooked everything up last night and it turned on, read cd's and what not, but absolutley NO sound, i have another deck, and tried that too, nothing. triple checked my wiring and i know its not that, i install all of my own sound systems, and in dash dvd's.

the only thing i can think of, is that on the back of the stock tape deck, there were 2 antenna looking cables, one male one female, havent seen that before. and also there are 2 wires that arent hooked up because they clip in to the stock deck, and there are no place to clip them into the harnesses or the sony. they are (I THINK) blue and yellow, unless they were really dusty and are black and yellow. Factory amp?? do i need to run power and ground to those wires somehow?? please help!!