Sounds like you may have a problem at the new deck. Did you install it yourself, or pay someone to do it?
I would doublecheck the wiring for the aftermarket radio, make sure you properly wired it - in particular, the constant +12v (red/green to connector C215, then yellow to the OE radio) and dimmer (gray/red to connector C215, then white to the OE radio). Sounds like they are connected together to me. Is it fuse 21 you have to pull?