The element is in a slot in tube which also doubles up as the flue for the gas flame.
You don't say which element (12v or 240v) you are replacing nor the make of fridge you have. I suspect that the element may be rusted tight in its tube so try easing it a little. Both elements are usually close to each other so pick the right one.
If it is a Thetford fridge go to the www. site and go to the spares section for your model. You should find an exploded diagram showing you all the parts and where they are located.
Hope that helps
CC member 18017873, October 2012