Subaru Problems? Ask a Mechanic for Answers ASAP
Hello I will help,
For you to have dual zones you need to have the controls but you also need to have the things they control like the doors in the HVAC case and the actuators mounted on the case.
To do this you have to strip the interior to the firewall, install the dual zone case and after you install the dash install the controls.
Please let me know what questions you have\