What are the details?
Do you mean that by shorting wires that the you think the head unit is connected wrong? Or did wires melt and cross? Do your console lights have power when your head unit does not? Does your antennae work?

This is a long shot, but one way you could have done this is the following: If your cd player has a lead wire for dimming its own display and you were attempting to connect it to the wire that controls your dash lighting, but instead connected the wire for your antennae to it, they would be on anytime your head unit has power. Very few (and mostly only very new) head units actaully pulse power through the antennae lead - it is constant 12v.

__________________
1982 Mercedes-Benz 300CD
1982 Mercedes-Benz 240D - stick