I recently moved home and discovered that my extractor fan didnt work in sync with my light switch. It doesnt have a pull cord switch either so the only way to work it is by using the iscolator swtich (which is on the ceiling). Its now packed in so I am about to order a replacement but wondered if anyone knows how easy it is to link it to the light switch. There are 4 available wires - blue, yellow, red and a thin brown one. I'm not sure if all the wires that I need are there or not?