2008 Chevrolet Cobalt vent problems

I had no air coming through the vents at all here to find out connector to the blower motor caught fire and took out the blower motor so I replace the blower motor and the connector that connects to the blower motor and it started working I could hear the blower motor going stong now but I don't have that much air coming out the vents I change the cabin filter and still I have that problem of low air flow going through the air vents