Simply put... It's because the failure mode of the blower control module is electric power on! (even with ignition off)... Disconnect the battery, or better... find and remove the 30 amp blower fuse. Remove and replace module with serviceable unit. Reinstall fuse or reconnect battery. Good luck! Note: If the blower is noisy at high speed or in cold temperatures, (if it vibrates or rumbles and squeals), now is the time to change it!
check the fueses check fueses
faulty blower motor resistor
Loose connection or blower motor is bad
down uner the glove box
becaus the 2004 Chevy impala does not have automatic lights and they have to be turned off manually
Replace the blower motor resistor.
Blower motor switch. Put it on High and it will blow when sitting still with the engine running.
The blower resistor is internally shorted to power and needs to be replaced.
I owned a 75 model Impala and the blower motor was located under the hood, passenger side of vehicle,down in the fender/fender well area, hiddenbehind a/c unit
The blower motor speed resister is burned out. This part is available from your local auto parts store.
my 05 Chevy impala brake light come on when my vehicle is turned off killing my battery.
connection could be loose. Or the switch might be going out