need help radiator fan not working
 

hello
today i change the coolent of the car and i did what ever was writen on the diy.when i start the car when it get warm the blower motor is giving hot air so that means there is no air in the line and now the fan doesnt kick on i checked the thromo switch it was hot too but still the fan is not kicking on please if any one can tell me what it could be.b4 the fan was working perfectly.