Hello, and welcome. the rear control unit just snaps into place. here is the instructions. if you need, i can post the console removal procedure.
ASE Certified Technician
Ase Master Certified, GM Master Certified Tech. Awarded GM Top performer,
your response was spot on. I was able to reseat the connector and the rear seat audio is now working again.
Thanks!
you are very welcome!!
thanks for using JA!!