Bathroom light and extractor fan won't switch off

[djfoot01]

Hoping for a pointer here. I'm not an electrician and can just about change a fuse so bear with me.

My wife was cleaning the downstairs batchroom when she heard a bang. The light and extractor fan went off. After checking the bulb, I replaced the 3A fuse in the switch. All came back to life and everything (I thought was good in the world).

When I came down in the next morning, the batchroom light and extractor fan were both on (they were definitely off when we went to bed)and wouldn't switch off using the pull cord. They go off when I turn off the fused switch.

I assumed it was a problem with the ceiling pull cord switch so I replaced it today. No difference! Any ideas what I could check for next before I call in a spark?

Many thanks...

 

[ericmark]

Can only guess but I would suspect the SCR or other electronic component in the fan which allows it to run on has gone permanent closed circuit.

In real terms only cure would be replace the fan.