It might be a good idea to check the continuity of the power wiring - both live and neutral conductors - from the prongs on the plug all the way to the motor - if you have good continuity then suspect the motor and or motor brushes - if you do not have continuity on both conductors then ignore the motor.
With a small multi-meter the switch should be easy to test - there should also be an overheat safety cut out on the motor - they sometimes fail. The most usual fault in my vacuum cleaner experience is a damaged power cable at one end or another - usually the plug end. An easy fix.
Good luck...
Peccavi
January 2011
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