Workshop Repair and Service Manuals GMC SIERRA
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Afterblow Enabling

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The afterblow mode can be enabled using the scan tool. Theafterblow mode allows the blower motor to operate after the enginehas been turned off. This operation of the blower motor dries theevaporator core, which reduces the amount of microbial growth whichcan create undesirable odors.

Use the following procedure in order to enable the afterblowmode:

Connect the Scan Tool.Turn ON the ignition, with the engine OFF.Build the vehicle with the scan tool.Select HVAC Control ModuleSelect Module Setup.Select Afterblow Option.Upon selecting the afterblow option a asterix will appearnext to the word afterblow meaning the function is enabled.Select the save option in the lower left of thescreen.

When afterblow has been enabled by the scan tool the blowermotor will operate at 68-percent blower speed for2-minutes 30-seconds to 4-minutesafter the engine has been in Key OFF for30-minutes.

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

The outside air temperature must be at least 21°C(70°F).The A/C compressor must have operated during the latest keycycle.The engine must be turned off for at least30-minutes.The system voltage must be at least12-volts.
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