Its seems widely known that the 1.9 l dohc run hot which leads to cracked heads.

Has anyone wired the fan to run continuously?

Is there a fan thermostat that can be replaced or set to come on earlier?

What is the normal reading on the temp gauge, centered or left of center?

 

The temperature is controlled (mostly) by the mechanical thermostat located in the outlet neck from the engine to the hose going to the radiator.

The ECTS (Engine Coolant Temperature Sensor) monitors the water temp, and sends a signal to the PCM (Powertrain Control Module) to turn the cooling fan on and off. The circuit is not adjustable.

The normal reading of the temp gauge is slightly left of center, but that might slew a bit simply from tolerances within the different pieces of equipment.

You could bypass the control portion of the fan with a simple switch, but remember that the fan, while robust, is not designed for 'continuous' operation.