Also make sure the hose from the bag door to the valve and the little spout and orifice it connects to in the door isn't clogged. I find those get dirty pretty fast.Could be the valve for the bag. There is a youtube video showing you how to remove the internal hose or replace the bag lockout valve. Just search youtube for how to change an electrolux 6500 SR control valve. If the bag full light comes on this is your problem.
truuuuuue !!!! the hose from the diagfram gets dirty tricking the vacuum sensor in beleaving the bag is fulkl i fix many system by cleaning the hoses one from bag thank one from bag door and one from cord rewind all connect to the diagfram in the center with the wheel you turn clean that i bet ya she worksAlso make sure the hose from the bag door to the valve and the little spout and orifice it connects to in the door isn't clogged. I find those get dirty pretty fast.