No power to the Omnivent roof extractor.

I have a 2009 Warwick Duo, anyone know what fuse the Extractor takes it's live feed from? All the fuses under the sink unit are fine, but no power to the switch.
Never used it until now, doing my winter service in readiness for a long hot summer

On one of my Symbols the fan power was from the lighting circuit tapped in behind the nearest light. It seems they pick up power from the nearest supply.

Alf

That sounds right, as the fan operates when the light is switched on, on my MH at least.

Thanks for your quick replies Gents.
I have now switched on the lights to check and nothing, also removed nearest dome light to see if I can see any joints in the cable and nothing.
I think next job is to switch the lights on and test to see if any voltage is getting through to the extractor switch, it could be the unit is "Kaput" as they say.

cheers, Bill.

Job done!
I was getting power to the Omnivent fan switch from the lighting switch by the sliding door. I removed the motor via the top of the van, split the motor and found one of the carbon brushes had smashed and stuck into its housing. I cleaned the brush up a little, sprayed it with WD40 and replaced everything.
All's well that ends well, that's what I say.