Why does my blower continue to blow after my climate control is off?

It is probably a Blower Motor Power Module failure. The blower motor power module is only used in vehicles equipped with Automatic Temperature Control (ATC) It is located on the lower right side of the HVAC unit housing, and is controlled by the Body Control Module (BCM) The Blower Motor Power Module is used on ATC systems only. It is relatively easy to replace. .Remove lower right underpanel silencer/duct. .Disconnect wiring connectors on blower power module. Remove blower power moduler retaining screws. .Pull blower motor resistor out of heater housing.