Hi there, I am Cam. I have some information to assist with this issue. First this is not normal. If you take a moment and read, this is the description of the vehicle blower operation.
The blower motor forces air to circulate within the vehicle's interior. The vehicle operator determines the blower motor's speed by placing the blower motor switch in a desired speed position or by selecting automatic operation. The blower motor will only operate if the blower motor switch is in any position other than OFF, and the ignition switch is in the RUN position. In manual operation, once a blower speed is selected, the blower speed remains constant until a new speed is selected. In automatic operation, the HVAC control module will determine what blower speed is necessary in order to achieve or maintain a desired temperature.
As the requested blower speed increases, the following conditions occur:
- The HVAC control module increases the amount of time that the blower motor speed control circuit is modulated to ground.
- The voltage and duty cycle, measured between the blower motor speed control circuit and ground, decrease.
As the requested blower speed decreases, the following conditions occur:
- The HVAC control module decreases the amount of time that the blower motor speed control circuit is modulated to ground.
- The voltage and duty cycle, measured between the blower motor speed control circuit and ground, increase.
Afterblow is a feature that dries the evaporator core by operating the blower motor after the engine is turned off. This reduces the amount of microbial growth that can create undesirable odors. The vehicle does not come equipped with the afterblow feature turned on. If the afterblow feature is required due to an odor concern, it must be turned on by the scan tool.
The following conditions must be met for afterblow to operate:
- The engine has been turned off for at least 45 minutes.
- The ambient air temperature is at least 21°C (70°F).
- The A/C compressor operated for more than 3 minutes.
- The system voltage is at least 12 volts.
Once the above conditions have been met, the blower will run for 4 minutes at medium speed.
If the blower is inoperative for times after starting then I would suspect a connection either power to ground to the blower, the blower motor, the control head in the dash or the controller for the blower motor join the duct near the motor as being faulty. A simple test light is what we can use to test. Do you have a test light?