Most American made dryers have a thermal fuse, a cut-off thermostat, a high limit thermostat and a cycling thermostat. LG is a South Korean made Dryer so they may name them different and consider the cut-off thermostat another high limit thermostat, that's why there's two on yours.
Ohm test the thermistor, make sure the dryer is unplugged when ohm testing.
At 70 degrees the resistance should be 9.3K ohms, 90 degrees would be 7.7K ohms. at 100 degrees wpi;d be 6.2K ohms, 120 degrees 4.3K ohms. If the thermistor reads outside of range then it needs replaced.
Here's the thermistor for your model:
6323EL2001B Thermistor Assembly
If your thermistor ohm tests good, If your meter has a temperature function (a meat thermometer will work) attach the thermocouple to the vent with the vent hose off and start a timed dry, high heat cycle. The drum must be empty and the lint filter clean. Target temperature is around 150*F. The first few rises can go as high as 190* - 200*F. After that the element should shut off at around 175*F and turn on around 140*F.
Here's the cycling thermostat for your model:
Here's the high-limit thermostat with the reset button on it for your model:
High Limit Thermostat 6931EL3003C