how to run the 5th motor without using the heater and thermistors

hello,
i am doing a 3d printer prusa mendal i2. i added another dispenser to the 3D printer that do not have any heater or thermistors. i want to run the 5th motor for the additional dispenser so what i need to change in the firmware to get it.moreover i tried to test and it by prevent the dangerous extrude, it was working but i have no need to use the heater and thermistors for the dispenser. so please let me now about the firmware modifications for the same.
thank you very much

I helped myself in the same situation by soldering a 100k resistor ( or smaller ) to the RAMPS-thermistor terminal.

Is it possible to run the motor without the use of thermistor and heater, please let me know asap.
Thank you very much.