Should be a brushed DC motor with fan speeds controlled by a resistor bank. Hi speed doesn't go through a resistor.
Not common for these motors to slow down from heat. Resistors go bad and electrical connections overheat and go bad but it normally works or it doesn't.
I know. I didn't really think the blower motor was bad, it's just odd how it blows fine at first. Also the coolant level has nothing to do with the amount of air that is pushed through the vents.
2006 Grand Prix GT S/C 109k - Modded Transgo Shift Kit, Gutted Airbox, Dash Cam, and Inlays. Retros soon to come. 2002 Grand Prix GT N/A 127k - Same as 06 Plus: Trans Cooler, DIY Aux Input, LED lighting, Suspension Upgrades, Tint, Retrofits. Sold.