Malfunction or failure of mechanical, electrical and electro-mechanical equipment, for example equipment used in manufacturing operations, is often preceded by an increase in the operating temperature of at least some portion of the equipment. Some pre-determined temperature, greater than the highest normal operating temperature of the equipment, is presumed or known to be indicative of impending equipment failure if no remedial action is taken. A resettable, temperature-sensitive device, containing a shape memory alloy actuator, pre-selected to operate at the pre-determined temperature, is disclosed. The device is placed in thermal contact with the equipment. If the equipment achieves the pre-determined temperature, the shape memory alloy actuator causes the device to display a flag or provide some other passive visual indication. Alternatively, or additionally, the actuator may trigger an electrically-powered alert including visual or audible alerts or a wireless communication.