my air speed on the ac/heat changes on it its own. it does not always match up to the air speed on the control.
Chances are it’s the resistor, cheap and easy fix. If set on high and works okay, then I would try replacing the resistor. If variable when set on high then might be the blower motor, further diagnosis required.
I’ve replaced the resistor. No change.
I’ve replaced the blower motor. No change.
It blows and changes speed on its own. If I hit a bump sometimes it will change speed.