How to test the rad fan (properly)

[nmik]

I am having problem with overheating after a strange event that I wasn't a witness to. My son was driving the car when it started misfiring and died. SES light came on and then disappeared after engine was restated and ran fine. I tried cleaning EGR system but had no access to the lower portion of the steel pipe so I never got to really cleaning it. Now it overheats even idling. Radiator fan dos NOT come on.
I'd assume I could hotwire the fan and see if the fan itself is functioning but it will not diagnose the relay or sensor or wiring. Is there a niftier way to diagnose the system?
Thanks!

[uibalnme]

Well, assuming no fuses are blown...there is a fan temperature switch at the bottom of the radiator. unplug it, and start the car. If the fans start running as soon as you start the car, then the problem would be that switch.