Mode 1 - Freezer boost: During the colder months when the garage temperature drops, the compressor will not run as often as needed to keep the freezer at the proper temperature. This is due to the fact that the thermostat for most fridge/freezers is located in the fridge compartment. When the freezer gets too warm but the fridge thermostat is still satisfied, the device will turn on the fridge light to add a little heat until the fridge thermostat activates turning on the compressor. The light will stay on until the freezer cools to a predefined set point. Note: I replaced the standard 40 watt incandescent bulb with a 9 watt LED.
Mode 2 - Fridge boost: During severe cold periods where the garage temperature is below freezing, it may become necessary to add heat to to keep items from freezing in the fridge. This mode will raise the temperature of the fridge slightly without warming it enough to turn on the compressor. This is accomplished by turning on the fridge light for only a short period of time.