Using this fridge defrost timer is easy. First, make sure your fridge is unplugged. Then, connect the wires according to the wiring details: connect Pin 1 to the switch common and one side of the timer power, Pin 2 to the defrost element circuit, Pin 3 to the other side of the timer power, and Pin 4 to the compressor circuit. After wiring, plug your fridge back in. You can use the rear - mounted switches to select the defrost or run cycle for testing. When setting the interval and defrost times, you can choose according to your fridge's needs, with interval times from 6 to 24 hours and defrost times from 15 to 32 minutes. Note that this timer won't work if the timer motor in your fridge's defrost circuit doesn't receive power all the time. For maintenance, keep the timer clean and free from dust. If you notice any problems, don't try to fix it yourself. Instead, contact a professional technician.