We describe an improved galvanic corrosion sensor element design that uses a multilayer structure to separate the anode and cathode. The improved design offers significant advantages in sensitivity and lifetime over conventional thin-film galvanic sensors. The sensor element is the key component in an automated corrosion monitoring system that is designed to periodically measure and record corrosive conditions on vehicles, portable equipment, and permanent structures. The information obtained by the system can be used to predict corrosion damage in places that are difficult to access and to guide improvements in corrosion inspection and mitigation practices.