Skoda octavia 1.6 se plus tdi cr 140

Hi Everyone,

So my skoda octavia 1.6 decided it didnt want to blow out hot air when i needed it most since we have snow its the wprst time..water pump seems all coolant and water levels seem fine no leaks and the pipes are hor near the engine however when you turn the heaters on blows out cold air?

Any ideas what i could try help would be much appreciated.