Check the plugs for the fans ..... sometimes they just have a bad connection. Clean and often they will work again ...
If not ... check if fans kick in when plugging them to a 12v source.
Can also check by putting a multi-meter on the plug and let the car heat up again if it doesn't read 12V at any point then there's no power going to the fans. (careful not to let the car get too overheated....)
/Thomas
Escort Cosworth '94