heater problems on 2004 Chevrolet Impala

how do you know if it is the heater blower or the heater blower resistor?

Asked by for the 2004 Chevrolet Impala
Generally when the blower motor resistor fails, the blower fan will work on the highest setting and not the others. If the fan doesn't work at all, check for power and ground signals to the motor and go from there.