Clicking noise coming from relay

Go to a parts store and get a relay. first figure out what is on. wipers, heater, are you using power windows? many things have relays. start the vehicle is it only when driving or at idle too. if it is at idle check under the hood with the vehicle in park.make sure it is not your AC pump "clicking" turns on and off when defrost and ac are off. but it clicks none the less. and check the master relay box should be on passenger side by the fender well. open it and look for the one snapping. touch if it helps determine. make sure you turn off everything and use one item at a time when checking.