Noise from Deodorizer. Hi I have a samsung side by side - when I open the fridge door I hear a

Question

Hi I have a samsung side by side - when I open the fridge door I hear a motor slow down to a "knocking" halt. It makes a knocking noise as it slows that is. The noise comes from around 2/3 of the way down the back of the fridge compartment. The deodorizer light is permanently on (I dont recall it being on before) - there are no smells (nor have there been any) anyway. Now that this has happened - the fridge part is not cooling at all. All I can hear is the permanently running motor from around the deodorizer area. The fridge is only 3 or 4 months old. Please advise. Thanks. Mark