After using my Eureka Upright Vacuum to clean-up a dust used to take the stains out of a carpet the brush would not start when I switched the vacuum to the carpet mode, after checking the belt and finding it in good shape I had to look into the problem further.
I took the vacuum apart and found that there is a Cherry micro switch that completes the circuit for the brush motor when the hose is inserted into it's holder. When the hose is pushed down into the holder it contacts a lever that activates the micro switch. The micro switch is "normally open" so when the hose is removed the lever comes off of the switch opening the circuit.
I tested the switch with a meter and found it to be open in both directions, N/C and N/O. After calling several appliance parts houses and learning that no one has any switches like the one I needed I tried to clean the one I had with alcohol by submerging the switch in alcohol and blowing it dry a few times it began to work.
It turned out that the switch was full of the dust from cleaning the carpet. The dust was so fine that it found its way into the sealed switch and prevented continuity to the brush motor.
So if this happens to your Eureka Vacuum, don't throw it out before you check the switch. The switch is located in the bottom section of the upright part of the vacuum right next to the vacuum motor.
