The microwave (upper) oven does not turn off when the door is opened. The three door switches (Door switch Item Number: AP2929295, Manufacturer's Number: 4375346 made by WHIRLPOOL) (part 51 in exploded diagram) have been tested and are OK. In fact, two new ones were purchased and the three existing ones tested the same as the new ones. So finally three of the five are currently installed. However, the problem persists. Needless to say, this is a very dangerous situation, especially since there are five children in the household.

What is the cause of this, and how can I correct it?