Under the passenger side of the dash, behind the a/c blower motor. It has a long wire connector attached to it. The GM part # you need is 89018643, and it lists for $38.65 plus tax at most GM dealerships.
Replace the blower motor resistor.
faulty blower motor resistor
There is a removeable panel below the glovebox. It is in front of the blower motor against the firewall. It has a wire connector from the loom and then it plugs into the blower motor
Recommend you check the blower motor resistor.
If you are referring to the blower motor resistor then it is inside mounted on the evaporator case.
To replace the blower motor resistor in a 2007 Chevy Impala, first disconnect the negative battery cable to ensure safety. Then, locate the resistor, which is typically found behind the glove compartment or under the dashboard on the passenger side. Remove the screws or clips securing it, unplug the electrical connector, and replace it with the new resistor. Finally, reassemble everything and reconnect the battery before testing the blower motor.
Right next to the blower motor
There is only one blower motor resistor and it is located in the evaporator housing.
In a 1988 Chevy 2500, the blower motor resistor can be found on the passenger side. It usually is behind the glove box.
resistor module is on the right side below the dash next to the heater motor next to the fire wall you will have to remove a kick panel by the glove box
The blower resistor controls the speeds of the blower motor Hi-resistance lower motor speed Lo-resistance higher motor speed
If you are referring to the blower motor speed control, and you only have one speed, then the blower motor resistor pack is defective and must be replaced.