Help

Help please. I have bought Wickes fan 199796 to replace a broken fan that came on when the light did, there is a switch outside which switches it off as well. The old one had brown and black cables connected but there were Alison two little red wires as part of the fan which were fed into what looked like a little box - two little red ones coming down and from main cable black and brown going up into little box. New fan only has a connection for live and neutral, have fitted brown wire to live and black to neutral as it was but absolutely nothing!!! Is it something simple??