The best glass cleaner that I have used is Hope’s Perfect Glass, which can be found at Lowe’s, Home Depot, and some supermarkets. If that doesn’t work, then you might try using rubbing alcohol, but you need to be careful that you don’t get any alcohol on the dashboard’s vinyl cover.
If none of that helps, then the only possibility that I can think of is that the heater core might be leaking. On a 1 year old vehicle, that’s not likely, but I suppose that it is possible. Have you checked the coolant level?