Volvo 6 CD stacker

[Skyedriver]

Hi, as previously posted, bought 2 940's this week, the poorer one has a 6CD stack in the rear right hand side well. Thinking of putting it into the better car which has the same redio/tape/CD player in the car but no CD. Is the car likely to have the main wiring within the harness somewhere or do I need to start from scratch.

Thanks
Tony H