3D printing module won't heat up

The known reasons for the heating problem are:
1) The Temperature Sensor connection is unstable or the Sensor is short-circuited. 
Please visit our troubleshooting tutorial to fix it
Or follow the instructions below to repair it:
If the plastic cover is broken or the wire touches the metal part, the sensor can't read the temperature. You can check it out by sending M105in Terminal,  with this issue,  you should see a minus temperature value(usually -15 ℃) or see a MINTEMP message shown as the picture above.  
To fix this:
A. Unscrew two hex screws with an Allen wrench. 
B. Unscrew the temperature sensor.
C. Make sure the cover is complete and then screw on the temperature sensor. 
D. Connect with Rotrics Studio and send M109 S190 to test the heating. 
2) The heat stick wire is disconnected. 
Temperature couldn't reach the target temperature after a few minutes.  
To fix this:
A. Unscrew two hex screws with an Allen wrench. 
B. Split the heat stick connection cover.
C. Solder the wires together and put on the covers. 
D. Connect with Rotrics Studio and sendM109 S190to test the heating. 