The wiring of the radiator fan provides the motor with power and control signals. It consists of wires, connectors, and sometimes, relays. From the vehicle's power supply or battery, a wiring harness runs to the fan motor and provides sufficient voltage to the fan. Control signals from the ECU or radiator fan thermostat wiring are also supplied. These control the operating parameters of the fan: when to start, stop, or change speeds. To perform properly and reliably, all the radiator fan wiring systems work together. A cut, break, or corrosion in any of the connectors within the wires will interrupt the required control signals to the radiator fan and power signals; this can lead to overheating of the engine.