Replace it. This is probably a sign of badly worn bearings that make it difficult for the motor to spin.
To change the heater blower motor on a 2000 Chevrolet Astro Van open your hood. After you open the hood you will see the heater box on he passenger side remove the four bolts holding the motor in and pull it out.
Under the hood, passenger side firewall, close to the heater blower motor.
The heater blower motor is on the interior passenger side. It is kind of a round shaped housing facing the floor.
down uner the glove box
There is a fuse under the hood for the blower motor.
fuse or relay most likely
The heater blower motor, which is under the dash is held in by three screws. After unscrewing, wiggle the blower out by pulling back the carpet layers to give extra room. Make sure that the replacement matches the original as there are two versions of the motor for earlier 2000 models.
INSIDE THE HEATER BOX BEHIND THE GLOVE COMPARTMENT.
you have a bare wire touching on your blower motor
find blower motor check for voltage on one of the three pins at blower motor, if so check for good grd. most likely ur blower motor is fualty.
replace the blower motor resistor. it is located on the firewall near the heater hoses.
If it has only high speed, the blower motor resistor has to be replaced to get all speeds back.