Heated Wiper Park Overview
WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
The HVAC controls the rear window defrost relay, which is located in the BJB. When the rear window defrost button on the FCIM is pressed, the HVAC activates the rear window defrost relay. When the rear window defrost relay is active, it provides power to the rear window defrost grid, and to the coil side of the heated wiper park relay, which supplies power to the heated wiper park grid.