Patent attributes
An alarm device for use with a vehicle includes an input connector for electrical connection with a vehicle wiring harness of a vehicle, an output connector for electrical connection with a trailer lighting receptacle of a trailer, and an alarm circuit electrically connected in series between the input connector and the output connector. The alarm circuit is configured to detect a presence or absence of an electrical signal supplied to the input connector for delivery through the output connector to an electrically powered component of the trailer. The alarm circuit is configured to deliver an alert signal when the alarm circuit detects the absence of the electrical signal.