Rear Blower Motor Speed Control
WARNING: This page is about a different car, the 2016 Ford Transit-350 HD, 2016 Ford Transit-350, 2016 Ford Transit-250, and 2016 Ford Transit-150. However, it is still accessible from the selected car via links, so may be relevant.
Rear blower motor speed controls are solid-state switches that use a PWM signal from the RHVAC control module to determine the desired rear blower motor speed. The blower motor speed controls then provide a variable ground feed for the blower motors.