How to Troubleshoot & Replace Whirlpool AP6008309 / WP3390719 Thermal Fuse (Disposable, One Time Fuse)

My Maytag dryer is about 19years old..through the years I have relied upon APP for all repairs including replacing the motor..this time since the dryer was not drying the clothes I decided to replace all the possible parts..the Thermostat, Coils, Flame Sensor, and a few others....about an hour later after also taking the time to vacuum out the lower pan and clear any debris. I was up and running drying clothes like a fiend. 

We replaced the Thermal Fuse that tested open. 

REPLACED THE THERMAL FUSE. 

Replaced it along with the Thermister. 

Replaced the thermal fuse. 

Made certain to clean all lint from fan area and cleaned vent replaced thermostat and thermal fuse. 

Replaced both thermostats and made a deep cleaning inside the dryer. 

Replaced thermal fuse (and did a very thorough cleaning of caked lint!) 

Replaced failed fuse. 

I replaced the thermal fuse and got a new belt because I broke the old one when removing the drum. As it turns out it was worn and would need replacing soon. I'm almost 70 and was able to do repair with the wonderful instruction videos for parts I purchased. They arrived as stated in good shape and bagged. I did a lot of sweating but it was worth every penny I spent. If this had not worked I probably would have been looking at a $500 cost of a new digital dryer, which I knew would not be something I could fix in the future. Thank you for your help and speed in getting my parts to me.