Chrysler voyager....CD

[Daveshell1995]

I have just replaced the head unit for my Chrysler Voyager 1998 model. The new unit went in great as all the wire looms etc were in the same place, so I did a like for like replacement.....however. The cd button when pressed does not activate the cd multi changer. I have checked the plug and this is fine. There is power going to the changer as I can remove the discs ok....Its just the button does not work...is there a problem when re installing radios......
Any ideas or similair experiances