An electronic control device for use in a motor vehicle includes an electronic housing for accommodating an electronics system that includes a circuit board, and a resistance sensor for detecting water that has penetrated into the electronic housing. The resistance sensor includes at least two sensor electrodes, each of which is present, at least in one section, in an uninsulated state with respect to the interior of the electronic housing, and a control unit that is configured to detect and evaluate a measured resistance value between the two sensor electrodes. The control unit is further configured to output a trigger signal when the detected measured resistance value or its deviation from a normal value meets a trigger criterion that is characteristic of a contact closure between the two sensor electrodes that is caused by the presence of water in the electronic housing.