Kenmore 70 Series Dryer timer not working
I have a Kenmore 70 Series electric dryer. Model #110.62712101 I bought this second hand about 2 years ago and all has worked great. A few months ago I decided to turn on the buzzer while drying a load of laundry (I have never had it on before). After about 3 hours I noticed I had not heard the buzzer go off. Went and checked and the dryer was still running. Normally I run it in auto-dry mode just out of convenience. It was still set where I had left it. The clothes were VERY dry to say the least.
Ever since then the timer has not worked. I have tried it in timed mode and auto-dry mode and they both have the same effect. Clothes dry fine but timer does not move. I read on several posts about a thermal sensor that might be the issue. Since this was a $20 part, I went ahead and replaced it. That did not resolve the issue. The dryer heats more properly now (in the past it seemed that it was on high heat all the time no matter the temp setting).
Rather than just replacing a bunch of parts I thought I would come to the experts. Any ideas what it could be? I figure ultimately it could be the timer itself, figuring the buzzer switch as just a coincidence. At $100 I didn't want to just replace it and it be the wrong part. Currently I set a stopwatch for 40 minutes and go turn the dryer of manually. Everything seems to work just fine other than it won't shut off automatically.
Just a note. I can open the door or turn the timer by hand to off and the dryer shuts off. I've not had an issue with heating, other than too hot from time to time. Advice is greatly appreciated.