could it be caused by a bad thermostat(s)? If I'm going to take it apart to check the wires, I'm thinking it would be worth it just to replace the thermostats if they could be the cause.

Here's some more info I should have had to start with: on low temperature, the auto shut-off works fine. So it's only on the regular temp setting does it fail to auto-shut off. Does this make it more likely that the high temp thermostat has failed? If so, can you tell me which part number? I'm thinking if I'm going to take it apart, I might as well replace it while I'm there. Unit is 20+ years old... thermostat won't last forever. Thanks.

Awesome. Thanks a million Eric.

Access is from the front. Remove the two screws near the bottom of the front panel, tilt it out at the bottom and pull down to release it at the top. Unplug door switch or just move panel to the side. The stats are on the blower housing on the left. The regular stat operates at 150° and the low stat at 140°. They should be marked, L150 L140.

Eric

am having same problem [ timer won't advance when using moisture control but will advance when using timer side of control] thanks for all thought on this problem.