When I push the "START" button the dryer will; start but stops when I let off the push button.

I have the machine apart and I have a meter to measure continuity and I have a diagram that I found inside the contro0l panel. I also have the machine apart (top and front is off as well as tub. Ihave vacuumed and cleaned the inside and I am ready to replace any bad parts and start to re-assemble. My problem is I cannot find the bad part.

I started with the "push to start switch" p/n 3395382. I Dis-connected it and it appears to be a "momentary contact switch" (can you confirm?). It shows open until I push it and shows continuity as long as I hold it down and then opens again when I release it. I assume it is good.

Next ther are 3 electrical parts on the metal tube surronding the heater element itself:
a "thermal cut off switch", p/n 3977394, ,I reemoved the connections and I get continuity.

a high limit thermostat", p/n 3390291. I removed connections and I get continuity

a "heater element it self, p/n 3392661. I removed the connections and get continuity. I also removed the coil and inspected and cleaned it and found no apparent defects.

Then on the blower tube there is "thermal fuse" p/n 3390719. I disconned and I get continuity thru it.

Also on the blower tube is a "thermister" I disconnected leads and I get an ohm reading of 9.46 and then 9.99K.

I don't mind ordering the part(s) i need but I am reluctant to repalce good ones un less they are going bad.

What should I check next? I would feel a whole lot better if I could indentify a bad part and replace it. I just don't know what to try next. Incidently altho the dryer is 10 or more years old it is like new. My wife and I are elderly and use iy very little.
Thanks and I will look forward to your suggestions
Doug Casey

how can I check to be sure it's the motor before I order one?