Light on 6000sr canister electrolux wont turn back on??turned dial whats it for?

Electrolux bag style C

This light indicates the bag needs changed. If you've done that, The possibilities are a clogged hose, clogged elbow at power nozzle, or on certain models a bad Control Valve Assembly. If yours has a dial on top, turn so the smallest dot lines up with the arrow. If it doesn't have a dial, you don't have to worry about a bad CVA. If you aren't using genuine Electrolux bags made by Home Solutions, then the bags pores will clog faster, which would cause the vacuum to shut off.

The Epic 6500 was actually manufactured in 1992 so in no way can be considered brand new.
First, make sure the plug symbol beside the dial is lit. This indicates the vacuum is getting power. If it doesn't light, there's a problem with the cord or the connections.
Second, turn dial on top of the vacuum so the smallest dot lines up with the arrow. This will allow for vacuuming finer dust for longer periods of time.
Third, check the afterfilter on the back of the machine. You do this by pressing the tab on the base of the tool caddy (in back) and lifting off. If the filter is dirty it needs replaced, or at least removed. Try the vacuum.
4. Detach hose from the vacuum and turn on. If it does, hold palm of hand over hole. If it shuts off, the control valve assembly is bad and needs replaced. The tubes connected to it will probably need cleaned. For this, It will need to be taken to an authorized Aerus Electrolux store for repair.
There are a few other things that could cause the vacuum to not run. See the following page for more information:

http://www.fixya.com/support/r7367127-electrolux_epic_6500_trouble_shooting

If the bag full light keeps coming on, you can first try adjusting the dial on top of the vacuum cleaner. If that does not work, then you need to change the control valve. This is an internal component of the canister and is directly below the dial. You will need to follow the instructions on a previous post to open the Electrolux plastic canister vacuum, and remove the bage cage. Once you remove the bage cage you can change the control valve, and this will solve your problem with the bag full indicator.

http://evacuumstore.com/

If the bag full light keeps coming on, you can first try adjusting the dial on top of the vacuum cleaner. If that does not work, then you need to change the control valve. This is an internal component of the canister and is directly below the dial. You will need to follow the instructions on a previous post to open the Electrolux plastic canister vacuum, and remove the bage cage. Once you remove the bage cage you can change the control valve, and this will solve your problem with the bag full indicator.

First thing is to push the circuit breaker button(reset button). If that dosen't work, check the belt. It could be broken.

check all the filters especially the one around the motor they could be clogged with fine dust

If this canister has a "bag full" light and auto shutoff, there is an internal diaphragm switch controlled by a dial on top of the vac. Set the dial for medium setting. Install a fresh bag and test again.
There is a pinhole in the throat of the vac which allows air to flow through a tube to the diaphragm. Check to see that it is not blocked with a grain of sand. There is a second pin hole in the corner of the bag chamber check there as well for blockage. If this vac is less than 20 years old the control valve for the diaphragm often cracks and needs to be replaced. You would access it by peeling ( like a banana) the soft rubber bumpers off the side of the vac and sliding the locking keys underneath the bumper out the front end of the vac when the bag door is open.Then gently popping the housing apart from FRONT to back. DO NOT try to pry the back housing off. Caution, this is normally performed on a cradle in a repair shop designed to hold all the components in place

oh, and as far as i know there's no secondary filter on this machine. or at least if there is, ours hasn't needed any tending to in at least ten years or so...

Turn the knob on top all the way to the right