B0286 05
WARNING: This page is about a different car, the 2009 Pontiac Torrent and 2009 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.
When the HVAC control module detects a short to voltage or an open/high resistance in the rear defog relay control circuit or the rear defog relay ground circuit for greater than 1 second.