The bearings are out of it. Replace Blower motor.
Check at the blower motor itself. Have it turned on and tap the end of the blower motor with a hammer. I did this and found out that the blower motor was going out. The blower motor is on the top passenger side under the hood. Also check the wire connections. Make sure they are seated good. If this includes for the heater then I would say the blower motor is bad.
The blower motor is drawing to many amps, replace the blower motor.
You either have a blown fuse, defective blower motor, defective blower motor switch, or a defective blower motor resistor pack.
Attached to the blower motor under the passenger dash
The blower motor resistor is located under the glove compartment in a black shroud.
It is usually under the dash on the passenger side right next to the blower motor. On some, it is mounted on the same bracket as the blower motor.
Try wiggling the electrical connector at the blower resistor. If wiggling this connector makes the blower go on and off, turn everything off and replace the connector before anything catches fire and burns the truck down.Next, when the blower is not working, set the fan speed to hi and try gently tapping the blower with a hammer. It that makes the blower come on the blower motor is bad and should be replaced. Also, use a test light or voltmeter to check for voltage across the two wires at the blower motor when it won't work. If voltage is present but motor won't work, motor is bad.
blower resistor is bad
you have a bare wire touching on your blower motor
Replacing the 1997 Chevrolet suburban blower motor resistor can correct your air output issue. The air output issue could because by other things.
Wright above the passengers feet under dash.
If the front blower on your 1999 GMC Suburban has stopped working, the issue could be related to a blown fuse, a faulty blower motor resistor, or a malfunctioning blower motor itself. Start by checking the fuse associated with the blower motor; if it's blown, replacing it may solve the problem. If the fuse is intact, test the blower motor and resistor for functionality. If both components are operational, the issue may lie with the vehicle's climate control system or wiring.