I have a 2010 Impala, but the heat is not blowing. It's on becasue I feel it at the vents.
The blower motor resistor needs to be replaced. It down by the blower motor, a little tight spot but easy to change. I would recommend buying a OEM resistor because they are just better, I have a 2010 Impala, it took 5 aftermarket resistors finally until I got one to last more than a week.
You may need to add to your radiator coolant, it's probably to low to push the fluid through the heater hoses.
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