Under the hood, on the firewall,on top of the a/c evaporator case is a thermal grid resistor assy. It has two plug in wire plugs. Unplug the larger one. if the fan stops. the resistor assy. ( you just unplugged it ) is shorted. Replace it.
Blower motor switch. Put it on High and it will blow when sitting still with the engine running.
check the fueses check fueses
no if all 4 wheels are on the ground and the engine is not running you will cook the transmission
faulty blower motor resistor
Loose connection or blower motor is bad
down uner the glove box
A faulty sensor in the engine block.
Replace the blower motor resistor.
A diagram for a 2001 Chevy impala 3.4L engine & coil pack firing order
it should be on the top of the heater core box in the engine compartment, it will have a wires running to it
What year, what size engine? 2004-2008 Chevy impala
what engine do you have in your impala?