If your HVAC controls are not working, it’s most likely because the module got unplugged during installation. Just make sure to keep your HVAC module plugged in (see image below). There is no direct plug from the HVAC module to the Dynavin radio. It connects through the main wire harness (through the CAN function). If you find that your heated seats or window defroster isn't coming on it's because it will only come on when the engine is running.

Pro Tip: if your car has dual climate controls, you can program the multi-function button (the one with the four squares) to go to the HVAC controls when pressed for quick access. To program the multi-function button, go to the “System” menu from the main menu and change the "Multi-Function" button setting to your preference.