My dryer stopped hearing and timer would not advance. Found no continuity when cycling thermostat was tested. Replaced this part and dryer worked perfectly for 4-5 loads. Now it is just as before: no heat and no timer movement. Is there another part or condition causing the cycling thermostat to fail, or is it more likely I just got a bad replacement part? Parts guy said it was probably just a bad replacement part, but I think the answer is probably not that simple. Please help. I am an old dude on Social Security and can't afford a new dryer. I will very appreciative of any help. Thank you.

Thank you for your answer, brobroffin. I have a long brush for cleaning out the area from where the vent attached to the machine to the outside. I have a brush that cleans the area under the lint trap, but I don't know how to clean out the transition tube. Could you please tell me where this part is and how to clean it. Thank you.

Mick also open the dryer door, pull the lint filter and look down inside where the filter was. See if there is a lint build up in there. This is the area just before the fan and moist lint collects there often.

Thank you brobriffin and thorning. Now that I think about it, when I first replaced the cycling thermostat, the clothes seemed to dry much faster than usual. Also the mice were particularly bad a few months back. I installed a new vent cover which is supposed to keep them out. I did check the part of the vent that is rigid and extends to the exterior of the house, but I didn't check the flexible part because I was trying to avoid moving the dryer out of the little cubby it is in, but it looks like I will need to do so. Unfortunately I threw my back out helping a friend move some stuff. As soon as I feel better, I will check the venting system. While I have the dryer out from the wall, I will check the thermal cut off as well.
When I was having all the mouse problems,
the vent cover I installed was the kind that has a baffle inside. When the dryer blows, it causes the piston-like part to rise and let the hot air out. When the dryer is not running, the piston thing drops down to prevent critters from getting in. Has anyone had experience with this kind of vent cover? Maybe I should go back to the louvrred style. Thanks again, guys.

Mick, I hope your back heals soon. I've not used that type vent cover however just monitor it to make sure it isn't collecting lint and causing a clog. When You feel better and clean the transition hose let us know how it turns out. Thanks for using Appliance Parts Pros forum!