The commutator serves to turn your oven on. It also enables you to select the various different functions (grill, fan oven, etc.), set the cooking time and choose the temperature.
Are you finding that you can't get certain functions to work? It's possible the commutator is the cause.
Does altering the temperature have no effect? Does your oven come on all by itself without you even touching it? You probably have a faulty commutator.
Find and order a commutator for your oven on our site. You're guaranteed to find the right one to fit your appliance.