If your fan isn't running, check the coolant temp sensor and wires. It's located on the driver's side of the thermostat water box. It has two wires running to it. Tan and black. If you unplug this sensor while the car is running the fan should turn on. This sensor doesn't feed the temp gauge, it's used by the computer to adjust fuel delivery.
If the fan doesn't turn on when you unplug the temp sensor, check the fan relay. That should be along the driver's side of the inner fender or strut tower.
The temp gauge actually reads from another temperature sender. It's bolted into the head near the front passenger side and has a purple wire. If your gauge isn't reading, this may be the issue.