There's a Fan in the Roof?

Reading the ever-helpful forum, I found there was a fan in the light pod in the roof which was supposed to draw the cabin air over a temperature sensor for the airconditioning. Some people complained about the buzzing, others said “what fan” (e.g. me) and one bloke reported that filling his car with Optimax suddenly started it working!

Mine wasn't working, so I followed the instructions given. Nope, still no luck. There are more suggestions on various sites (try AndyP's) which I might get round to sooner or later. In the mean time, here are a few blurry piccies of what I found - just in case it helps.

the pod

cover off

cover off side view

dangly fan