Sometimes, you may need to replace a malfunction thermistor. These could be some helpful tips:
1) Cut the two small red PTFE sensor wires( usually 22AWG), some Keenovo Digital Controller has them in a white sleeve, cut the white sleeve in this case.
Cut close to the thermistor bulge. Never Try to open the patch/bulge or cut into the heater surface.
2) Connect the new thermistor( NTC100K Thermistor B 3950-1%) to the two red wires. There is no polarity here.
3) Attach the thermistor to the heater surface. High temperature silicone RTV cement is recommended for a permanent installation.