Audio Systems: 1992 chevy truck radio CDM (equalizer)

Question
I have a 1992 chevy truck that had a after market CD installed.  I am taking it out and placed an original CDM, Tape equalizer, (radio head was already there). All original connections are there.  The radio unit comes on, the tape player plays and the clock is  working fine but I am not getting any sound. On the CDM, all plugs are plugged accept one on the top but I don't have another connector loose.  How do I tell what is missing from the connections and fix the problem so that I have sound?

Answer
You have the wrong CDM or the wrong  tape player, the audio from the radio is inside the CDM
but it needs to go tot he tape and come back to the CDM to play because the EQ is in the tape player  the unit on top is just a controler

bad CDM or wrong tape eq