Originally Posted by j.hammond1

I have recently bought a sapphire cosworth and the engine fans do not work. I have replaced the wiring harness and radiator fan switch. When I bypass the radiator switch the fans work, they do not come on however when the car is running and gets hot.

Does anyone have any idea how to fix / diagnose this, I'm tempted just to buy an override switch but I'd prefer to fix the problem properly.