Audio Systems: DISPLAY ON CAR STEREO, jeep grand cherokee laredo, jeep grand cherokee

Question
I HAVE A 2004 JEEP GRAND CHEROKEE LAREDO SPECIAL EDITION.  MY CAR STEREO IS A MULTI DISC CD AND IS EQUIPED WITH NAV.  MY PROBLEM IS IF THE CAR HAS BEEN TURNED FOR AWHILE THE TIME, AM OR FM DISPLAY WILL ILLUMINATE BUT, IF I TURN THE VEHICLE OFF AND RESTART IT MY DISPLAY IS GONE AND ONLY MY VOLUME CAN BE CHANGED NOTHING ELSE WORKS.  WHAT'S THE FIX

THANKS FOR YOUR HELP

Answer
I have asked around about this one as it is a bit odd.  The common thread in all my discussions has been an installation problem or connection issue.  There should be 2 sources of power going to the unit.  One switchable and one constant.  The switchable is so that the unit can only truely be on while the key is in and either in accssory mode or on.  The other provides standby voltage for the memory etc.  Recheck all of the wiring.  Look for cracked insulation and/or broken wires.  Consult an installation sepcialist if you are unsure about tracing the wires.
Dan