The fan will only run at max speed and is not variable

If you have a variable speed blower motor, a bad motor speed controller can keep it running even with the key out of the ignition. See this post on blower motor controllers. https://ricksfreeautorepairadvice.com/blower-motor-wont-shut-off/

DESCRIPTION The dual radiator fans are mounted to the back side of the radiator . The radiator fan consist of the fan blade, electric motor and a support shroud which are all serviced as an assembly.
OPERATION COOLANT TEMPERATURE
A/C PRESSURE TRANSAXLE OIL TEMPERATURE Fan Operation Speeds: Initial Max Initial Max Initial Max Fan On: 104°C (220°F) 110°C (230°F) Fan Speed Duty-Cycles (Ramps-up) from 30% to 99% 1,724 Kpa (250 psi) 2,068 Kpa (300 psi) Fan Speed Duty-Cycles (Ramps-up) from 30% to 99% 96°C (204°F) 111°C (232°F) Fan Speed Duty Cycles (Ramps-up) from 30% to 99% Fan Off: 101°C (214°F) Fan Speed Duty-Cycles (Ramps-down) from 99% to 30% 1,710 Kpa (248 psi) Fan Speed Duty-Cycles (Ramps-down) from 99% to 30% 89°C (192°F) Fan Speed Duty Cycles (Ramps-down) from 99% to 30%

These have a variable speed radiator fan. I'd check the radiator fan controller --they're a known problem.

http://ricksfreeautorepairadvice.com/car-overheats-chrysler-vehicles/

There are many variations of engine suspension tyres and road surface that willhave aneffect on max speed, even tyre presures can make a difference so no figure can be given. Sorry but can't be more specific

Change resistor to fan

Turbo Radiator Fan

The radiator cooling fan is a variable speed electric motor driven fan. The radiator fan assembly includes an electric motor, fan blade, and a support shroud that is attached to the radiator. The radiator fan is serviced as an assembly (fan motor/fan/shroud).

The variable speed radiator fan is controlled by the Powertrain Control Module (PCM) by way of a Pulse Width Modulated (PWM) signal. The duty cycle ranges from 30% for low speed operation then ramps-up to 100% for high-speed operation. This fan control system provides infinitely variable fan speeds, allowing for improved fan noise, A/C performance, better engine cooling, and additional vehicle power.

To control radiator fan operation, the PCM looks at inputs from:

Engine coolant temperature
A/C pressure transducer
Ambient temperature
Vehicle speed
Transmission oil temperature (automatic transmission only

HENCE CHECK THE PCM

the fan speed is variable to save fuel, the fans don't run unless the engine gets really hot, about 230 F, that is well past the middle of the gauge if u havce one, so the fact they run with the AC on means the system is almost certainly functional as long as u are not showing an engine overheat, are U?

Check the blower motor resistor pack is not faulty.
The resistor pack (for speed control) is usually located in the blower fan ducting in the air flow .

This is a variable fan that changes speed with engine conditions. Some actually don't operate at all when the engine is cool. Older fans ran continuously and wasted engine power.

sounds like the engine coolant temperature sensor.