Tbird 93, radio wiring

Well the topic says it all.I have a 93 tbird.I have done saw all the waire diagrams but the wires in my car dont match.But i hav a Yeloow,Red and a black wire,someone b4 me cut the wire harn.So i hooked the red to RED / w black line in the wire,yellow to yellow and black to black but i cant get the mem to say in the HU.I know the HU is good cause i put it in my Cutlass when the mem didnt stay.The HU is a pioneer 6800.

Scoot