How to Troubleshoot & Replace Frigidaire AP3866842 / 134587700 Control Thermistor

Based on looking through the videos, I chose to replace the heating element and the two thermostats. The dryer is in a difficult place to service, so I wanted to change out what might have failed in one session. The videos were the most helpful in disassembly and fixing the problem. The only down side was that a new thermostat was included in the heating element assembly, so I have an extra part to return. 

Diagnosed the problem and reordered the parts n replaced them 

Ordered a new sensor and son installed it in about 10 minutes. It now works great. (The lint trap had become plugged and it burned out the sensor.) 

Thermo was bad 

I order the sensor from Appliance Parts Pros. I watched a video on YouTube on how to take the dryer apart, it was easy once I saw how it was done. I replaced the part, put it back together in about 20 minutes, and the dryer worked again. Appliance Parts Pro is excellent to work with! 

Ordered the thermistor as it did not read 50 K ohms (it was closer to 43 K) . While waiting for it to come in I read some more stories and one about finding bad solder joints on the "brain" board. Pulled mine out and sure enough the solder joints where the relay was attached (drives the heating element) were cracked and distorted. Took my soldering iron (any will do) and re-flowed some solder on the the joints behind the relay. Dryer now puts out plenty of heat and no issues. Will still install the thermistor as an added benefit since the new one does read 50 K ohms and it is used to set the levels of heat. 

Saturday, October 10, 2015, our 10-year old Frigidaire stacked dryer was running but there was no heat to dry the clothes. I checked the Dryer Manual which did I.D. the parts that could be the problem. I did an Internet search and found your Website to be extremely helpful, especially the "how-to videos." I then did a continuity test on the parts controlling the dryer heating and found the heating element to be the problem. The element was burned/broken which resulted in no continuity. Sunday evening I ordered parts (heating element, drum bearing, high temperature lubricant, and a thermistor). Early Tuesday morning the parts were delivered by Fed Ex, and by Tuesday afternoon the dryer was repaired and functioning as designed. Best of all, my wife is very happy, which makes me happy too, thanks to AppliancePartsPros.com. 

Replaced it with new one from Appliance Parts Pros. The dryer would stay bring in the middle of a cycle, indicating the load was dry when it wasn't. Then it would continue to beep the remainder of the cycle and the clothes would never be dry. After replacing the thermistor it has stopped being and is running as normal. The part was easy to replace, the hardest part was putting the bottom cover back on the dryer. 

I looked around the web and found that appliancepartspros.com was the only website I could find that had accurate, step by step videos to help me troubleshoot and repair my dryer. Some videos from other websites were close but but missed steps. The videos made it easy to follow.I also used this as an opportunity to clean out the dryer and replace part that were starting to wear down. A mini overhaul to extend the life our our dryer. 

I replaced the THERMISTOR, which ya'll said is always the problem...and gave the brainy-units behind the control-panel a shot of CRC Lectra-Motive electric parts cleaner, just to either completely destroy the dryer, or shock the Morse-code out of the switches. The "clips" which "hold" the face-frame stiles to the case kept falling off as I tried to re-assemble the dryer, which elicited first laughter, then cursing, then prayer, then squeezing them shut just a little with pliers, which truly was Divinely-inspired. While I was in there, I vaccuummed it out, of course, and marveled at how incredible cheaply-made this thing is, then re-glued the foam gasket between the fan housing and the exhaust tube, as it had broken and fallen loose, allowing who-knows-what-all to escape. I did find your video extremely helpful, and was optimistic about a woodworker's chances of fixing the dryer. My wife will be letting me know how I did!