Volvo 850 Deck Problems

Hey,

I was doing a pioneer deck install on a 1996 Volvo 850R and the only way to get the deck to power on was to cap the constant 12v+ and ground and the switched 12v+ and ground together (all 4 wires).   I tried just doing the harness constant to constant and ground to ground but nothing worked.  It currently turns off and on with the key just fine but it can't keep the memory.  Also the deck now always thinks there's a cd in it and there isn't.  It worked just fine when it was in a previous car.  Any help would be very appreciated.

Thanks