When Vacuum is on no light - Dyson DC25 All Floors Bagless Upright Vacuum

It won't work properly if there is a jam or something cought and wound round the roller... even if it's just a lot of string.

usually the lights are to indicate service is required , if it still works properly, ignore the lights ,just a time coumter triggered by use

The brush drive mechanism may be jammed

On your stand there are blue lights that show when it is charging the vacuum. If plugged up with out the vacuum on the base the lights do not show. Once you set the Vacuum on the base the blue lights indicate that it is charging.

When switched on the vacuum goes through a self diagnosis test. Lights will come on for a while, then go out. If everything is okay, then the blue "Optimum" light will come on and stay on. If it turns of, a red indicator light should come on providing information on what's needed; i.e., filter or bag change needed.

Light bulbs on vacuums are pretty basic. They are not made by the vacuum cleaner company. Here is a list of vacuum cleaner light bulbs

Im going to guess you have an Electrolux Tank. the control valve inside probably went bad. normally i just disconnect it. Do no try to take it apart if you don't know what your doing. take it to a vacuum shop.

This is fine it is an indicator light that the computer is working.

The problem was a sticking switch that was not being reset. The vacuum on/off switch mechanism is comprised of two switches. One is the main switch that turns the vacuum on and off. The second is a shut off switch that gets tripped when the full bag sensor is engaged. This second switch is supposed to get reset when you push the on/off switch on the outside of the machine. The full bag shutoff switch was stiff and it, therefore, was taking a couple of presses of the on/off switch to move the shutoff switch back into the running position.