2.5 mm Hex Key, Small Flat-head Screwdriver
Be sure to power OFF and unplug your printer before removing any electronic components.
Look under your extruder carriage and locate the two hex screw heads towards the outside of the heating block. Using your 2.5mm hex key remove the hex screw that is holding the thermocouple ring in place. This will free up this end of your thermocouple cable (put the screw back into the heating block or secure in a safe place).
Look on top of the extruder assembly and you will notice several cables that exit into a black spiral cable cover. Notice the two cables that are exiting via the rear of the extruder assembly (usually with a silver cable sheath)...these are your thermocouple cables. Carefully maneuver the ring end of the thermocouple cable out from underneath the assembly and away from the stepper motors. Slowly unravel the twisted black cable cover that covers all of the extruder cables and separate the thermocouple cables. If you have to cut through zip-ties to free the thermocouple cable be careful not to cut any cables.
The thermocouple cables will lead you to the bottom of the printer where you will see an electronics panel that is hiding your micro-controller. You will need to remove this panel in order to un-plug the thermocouple connector. Using your 2.5mm hex key, remove the screw highlighted by the green arrow below. Once removed, place the panel, the small screw, and the nut in a secure place.
Looking at your micro-controller you will notice various connectors, cables, and "circuit chips". On the bottom side of the picture below you will notice 5 rectangular driver chips...these are your stepper motor drivers. On the same side as your stepper motor drivers you will find a green 4-Pin connector for your printer's thermocouples. Using a small flat-head screwdriver un-screw the 2 screws that hold in your thermocouple cables into the green 4-pin connector. Be aware that this 4-Pin connector holds both your left and right extruder thermocouple cables. Only remove the cables that you need.
You have now removed your thermocouple cables. Please remember to replace your bottom electronics cover panel.