1993 caravan C/V stereo...

I'm looking to know what wires do what on the back of a base stereo, no tape player, and/or one with a tape player. Becasue the one my dad has(i work on it for him), has an AM/FM only stereo, and i wanna put in one with a tape player for him, and i need to know which wires on it's harness go to what, like speakers and stuff. I could go buy the harness for aftermarket stereos and get the chart from that, but we're nto putting an aftermarket reciever in it. Anyone know of somehwere online or something that has a chart with that stuff on it?