Resurrecting an old thread here, but someone might find it useful ...
These machines have a permanent live and neutral down to the head which powers the lights, then they have a switched neutral that actives the roller.
The 3 common faults I've come across with these is:
1) In the solid extension tube, if you take it out, near the bottom is a small panel that unscrews and a wire in here often breaks.
2) There's a switch inside the hose, I've not had one of these fail but I have had a track burn out which can be resoldered (see attached photo)
3) The PCB/motor inside the head fails, this is a straight head replacement.
If anyone wants to check the wiring on theirs:
Hold the hose in the position you would if you were using it and look down, the connections from left to right are:
Live / Switched neutral / Neutral.
Hope this helps some of you.