Keep your cool
What year and make car are we talking about? On several models the cooling fan is controlled by the temp switch in the a/c system. This switch is generally located by the a/c condenser in some case is green and is threaded into the side of the reciever dryer housing. If you want to do a quick check of the fan itself you can use a paperclip and close the circuit between the two wires. If the fan comes on, then most likely it's the switch that has gone bad. If your temp goes that high with the a/c on, where is it without air? You may suspect the thermostat as faulty as well as the flow of coolant through the system if you end up with a puddle in your driveway while it's running. Are you losing coolant? Look at these few things first and give a few more details on the car we are troubleshooting.
"Tell me and I will listen, Teach me and I will learn, Show me and I will accomplish, Involve me and I will succeed."
'84 300SD 256,000 Gold on Brown (Mileage Award)
'86 300E 246,000 Blue on Tan