Where is the auto defrost hole?

Fox, Fantastic answer on here, but my husband would like to know where the auto defrost hole is, so we can have a look at solving the problem.
We have had our samsung fridge/freezer for 18months, has pretty much made the buzzing sound every month from the word go! Now the fridge is warm at the top and cold at the bottom, fridge temp indicator flashes when fride is open but is still saying it's 2C - even though it's definately not!
Will try switching off for 48hours, but would like to solve the problem completely.