Maytag dryer not heating up on all cycles and not properly drying clothes

The dryer heating element is not heating up on certain cycles, such as the wrinkle release. Have replaced both thermostats with no change in problem. Dryer vents and ducts are all free and clear. The blower fan is working properly as is the heating element itself. Want to know how to properly test dryness sensor bar and the dryness control panel. Can’t keep on buying parts that don’t solve the problem. This stacking dryer/washer is a little over 2 years old. Please help

You will need a meter to check things, preferably one with an amprobe.