Dual Climate Control not working right
 

Hi all, my dual climate control isn't working quite right in that the temp on the passenger side never changes independently of the drivers side. Meaning that if the driver has it on 65 and the passenger on 80, arctic cold air still comes out the passenger side. I've found a climate control unit for a decent price but wasn't sure if that would fix it. Anyone have any ideas? Could it be something else?