2003 100 Series LC, JBL Amp is dead..what else does it effect?

[TheRoadSMITHS]

The Factory amp is toast and also the rear HVAC panel and dash switch no longer work. Are they associated? Need to replace the AMP and while after market OEMs are cheaper, concerned that if the 2 issue are related, then the HVAC controls will. still not work. I seemed to recall mentioned that unplugging the amp will cause the rear AC controls to stop working. Is that true? Thanks