Cooling Fan not engaging

The system is pretty complex. Toyota build in a fail safe that if the fan switch fails the fan runs all the time. Take off the connector at the fan switch with the key on the fan should run. If not you have to trace the fan circuit on a wiring diagram, it is complex and involves several relays. There is a company that independent auto repair shops "buy" their information from that offer a very reasonable service to do it yourselvers. You can get a one week subscription or year subscription very cheap. The information is year make and model specific repair procedures, service bulletins, component locations, wiring diagrams ect.... great quality information same as the professionals have ,much better than generic workshop manuals from parts stores, much cheaper than the factory manual try http://bit.ly/mitchell_repair_manuals_online and get an online repair manual subscription.