Fridge light only comes on when Freezer door is opened?

I have a Fysher & Pykel Fridge/Freezer (with the freezer being on top) and after coming home from holidays we noticed that the fridge light does not come on when you open the door. However it will come on if you then open the freezer door. When the fridge door is shut and you open only the freezer door you can see through some vents that the fridge light is on. Is there a switch or something that has been reversed?