There are some simple tests that can be done to check the heating function of a Thermomix®.
Test 1: Place an empty mixing bowl in the TM5, set the Thermomix to 3 min / 250°F / Speed 1. If the temperature is not reached, it is likely the heating mechanism is malfunctioning; call Service at 888-867-9375 for next steps. If the temperature is reached continue to Test 2.
Test 2: fill the mixing bowl with 1 liter (or approximately 35 ounces) of water at room temperature and set the TM5 to 8 min / 212°F / speed 1. If the temperature is not reached, it is likely your TM5 needs service, call Service at 888-867-9375 for next steps.