Abstract: A moisture sensor to sense rain on a windshield. The sensor members on the outboard surface of the windshield are uncoated and directly exposed to any moisture accumulation on the sensor. Leads connect the sensor to an electrical signal generator and receiver and are insulated from each other to prevent direct electrical interconnection therebetween and subsequent shorting of the sensor circuitry. When moisture is on the sensor, the nature of a monitorable electrical signal passing through the sensor changes and is detected. In response to the altered signal, the windshield wipers are actuated.