Dodge 2009 Caravan Owner's Manual page 108

106 UNDERSTANDING THE FEATURES OF YOUR VEHICLE
The area on the rear fascia where the radar sensors are
located must remain free of snow, ice, and dirt/road
contamination so that the BSM system can function
properly. Do not block the area of the rear fascia where
the radar sensors are located with foreign objects
(bumper stickers, bicycle racks, etc.).
Sensor Locations
The BSM system notifies the driver of objects in the
detection zones by illuminating the BSM warning light
located in the outside mirrors.
BSM Warning Light