After Blow Mode
WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
The Instrument Panel Module (IPM) can be programmed to operate the blower motor for 4 minutes after the vehicle engine has been shut off. This blower operation dries evaporator core which reduces the amount of microbial growth and undesirable odors. The after blow mode must be enabled by a scan tool. In order for the IPM to operate the blower motor in after blow mode, ambient air temperature must be 70°F (21°C) or more. A/C compressor must have been operating for more than 3 minutes, the engine has been turned off for 45 minutes and system voltage must be 12 volts or more. See AFTER BLOW ENABLE PROCEDURE under PROGRAMMING.