GM Service Manual Online
For 1990-2009 cars only

The afterblow mode can be enabled by using the scan tool. The afterblow mode allows the blower motor to operate after the engine has been turned off. This operation of the blower motor dries the evaporator core. That reduces the amount of microbial growth which can create undesirable odors.

Use the following procedure in order to enable the afterblow mode:

  1. Connect the scan tool.
  2. Turn the ignition ON, with the engine OFF.
  3. Select HVAC Module.
  4. Select HVAC Systems Automatic.
  5. Select BCM.
  6. Select Module Setup.
  7. Select Afterblow Option.
  8. Upon selecting the afterblow option an asterisk will appear next to the word afterblow meaning the function is enabled.
  9. Select the save option in the lower left of the screen.

When afterblow has been enabled by the scan tool the blower motor will operate at XXX percent blower speed for XXX minutes XXX seconds to XXX minutes after the engine has been in Key OFF for XXX minutes.

The following conditions must be met for the HVAC module to operate the afterblow:

    • There must be an outside air temperature of at least XXX°C (XXX°F).
    • The A/C compressor must have operated during the latest key cycle.
    • The engine must be turned off for at least XXX minutes.
    • The system voltage must be at least 12 volts.