I have fitted a new cooling fan on a 53 plate fiesta and now its not working! I have given it direct power and it spins up fine but when the engine runs up to temperature its not cutting in.

Help!

 

When engine is running check whether the permanent supply is live or neg, so obviously the other one is switched and is missing, if it has a rad fan switch(might be ecu controlled) bridge switch, if it nows works, replace switch, don't overly rely on gauge temp to be accurate though.
tabetha