The switch that you are describing is for the high temperature alarm. That component is shown in the image below. The orange light is a power light. The red light is on when high temperature is detected. Since the red light is on, the high temperature sensor is tripped. That is why the buzzer goes off whenever you turn that switch on. That switch allows the buzzer to sound when it is turned on. It silences the buzzer when it is turned off. If the temperature in the freezer is higher than normal due to it just being turned on or from new food being added, then the alarm is probably working normally. If the freezer is at or below the normal operating temperature of zero degrees, then you probably have a bad high temperature sensor. If necessary, check the temperature inside the cavity of that freezer using an accurate thermometer. Place the thermometer between some frozen packages of food and leave the door closed for several hours to get an accurate temperature reading. This will help you understand whether you have a component problem. If you need help with repairing the freezer, reply with additional details such as the actual temperature inside the freezer.
The owner's manual has additional information about controls and troubleshooting. Here is a link for your owner's manual in case you need it: