Vent's not working. No Heat/AC

Hi, my name is Devin. I am an auto repair expert with the Car Genius team here at RepairPal. I'm sorry to hear you're having trouble with your Passat. Since the heat and AC aren't working and the vents are inconsistent, something may have been reassembled incorrectly during the heater core replacement. Sometimes, when the heater core is replaced, connections to the blower or blend doors can be disrupted. I would inspect all of the components removed during the heater core replacement for proper installation. If you need more advice, have any other questions about your vehicle, or would like to get connected to a RepairPal Certified shop near you, we have you covered. Give us a call at 877-913-1554, and we will happily help you out!