Bathroom fan controlled by dimmer switch

[sparkwright]

I came across a bathroom fan that comes on with the lights via a dimmer switch.

My gut reaction was to change it all, with a 2 gang switch consisting of one dimmer and one on/off switch.

And then I thought, do I actually need to?

What do you all think?

 

[flameport]

Is the fan directly powered via the dimmer, or is it just the switched input so that the fan runs on a timer?

 

[sparkwright]

The fan goes off as soon as the dimmer is turned off - I think it was intended to be on a timer, I'm told it is a humidity fan, but apparently the electrician couldn't get it to work correctly...