The dryer was running, we opened the door to take some stuff out and closed it again and it would not start. The light comes on when the door is open so there is power. I tried all the cycles and settings. Nothing. I can hear the timer motor running and I can hear the relay click once when I press the start button. Subsequent presses of the start button do not make any more clicks unless I turn the timer to a new cycle or open and close the door. We have had some problems with the timer in the air fluff setting, where you have to jiggle the timer to get it to start after pressing the start button. But we never had similar problems in any other cycle and I have tried them all this time. I used an ohm meter to check the door switch (both contacts, not just the one for the light), the high limit thermostat, cycling thermostat, thermal cutoff and thermal fuse. All are good. The heating element is good too. I also removed the red wire from the timer and used the meter to verify that the circuit opens when the timer is off and closes when it is in any cycle position. I am starting to think it might be the electronic control, but it looks fine and it is the most expensive part, $112.21! Is there a way to determine if that is the problem without buying a new one? What else could be the problem? The only thing left seems to be the drive motor.

I used an ohm meter to check the thermal fuse, high limit thermostat, cycling thermostat, and thermal cutoff. All are good; not blown or open.

Thanks Gene,
I was beginning to think I needed to check the motor. I had my son help and plugged it in, turnd the timer to a run setting, held the door switch, pushed the start button and reached into the drum and turned it by hand. No sound or hint of power when turning it in either direction. But I haven't figured out how to reach the motor. Do I have to remove the blower to get to it? It looks like I could test the motor winding resistance by measuring from the thermal fuse to timer switch 4 where the white wire from the signal guard switch comes in. The wiring diagram shows that I would be testing from motor 4M to 5M by doing that. And that would not require any (more) disassembly. I did that measurement and got 2 ohms.

As I study the wiring diagram it looks more and more like the electronic control cannot prevent the drive motor from starting. It seems like all it would do is control the timer motor in response to the moisture sensor. If I am right about that, then it looks as if I have ruled out everything except those two switches on the motor, the one from 5M to the start winding and 6M and the one from 1M to 2M. The 2 ohm reading implies the switch that engages the start winding is closed, which is reasonable since the motor hasn't startged yet, and the 2 ohm COULD be two 3.8 ohm readings in parallel. It did flash between 1.9 and 2.0 on the 200 ohm scale, which is the lowest on my meter.

I did try measuring voltage at the fuse. It went to 120 when I pressed the start button. Haven't checked voltage at the start switch yet. I'll do that next. My wife said it was the start switch from the beginning. After all, you push it and it doesn't start!

Now check the timer according to the chart on top of the wiring diagram and all wires from the timer to the motor.
If the timer is bad, replace it.
If there is nothing wrong with the timer or wires, then the part left is the motor.

Gene.