OFF mode
WARNING: This page is about a different car, the 2007 Pontiac G5 Pursuit, 2007 Pontiac G5, and 2007 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
When the OFF position is selected, the HVAC control module applies ground to the fan off input within the HVAC control module through the off blower motor control circuit. When the HVAC control module receives this input, any air conditioning (A/C) request will be cancelled and the A/C request LED will turn OFF.