The Auto timer on my oven (C367EXH) has stopped switching the oven off until the start time when I ask it to delay. There is no 'clunk' that I would normally hear as the oven switches off until the start time when setting the temperature. All timer functions are working correctly apart from the oven switching off until the timer reaches the start of the cooking time. Is there a cheaper part to replace or is the only option the whole timer module? It's a lot to spend just to get the auto timer working again!