What's the time frame for the progress from "sensing dryness" to "cooling?" Very quick, or longer than a drying cycle usually takes? If the machine isn't heating it should display a fault code. A fairly common issue with the gas models is a bad igniter.

There's also a flame sensor module, the gas regulator valve, automatic reset overheat thermostat, manual reset overheat thermostat, exhaust temperature sensor, and motor control module which also controls operation of the gas burner.

You might check if the manual reset overheat protector has triggered. Typically this is is caused by an exhaust obstruction, so check for clogging somewhere if that's the case. Other than in the exhaust ducting leading outside the house, there can also be lint accumulation behind the grill on the left side of the drum where the lint bucket mounts.

The overheat protector is behind the machine's front panel, on front of the heater box beneath the drum. Access thusly: UNPLUG the dryer. Remove the lid. Carefully pry out the two lid bumpers at either side near the front corners. Remove the two screws beneath. Raise up the top deck, have an assistant hold it up. Remove the two screws at the edge of the front panel. Spread the sides of front panel just a little so the tabs that latch into the door grabber can clear. Pull the front panel forward and lift upwards to remove it. Be careful of the ground wire that clips to the lower edge of the panel. Shouldn't be necessary to remove the clip, you can turn the front panel aside enough to access the overheat reset button. Locate the reset button on the overheat thermostat and press it. The reset button is a large red button on electric models, but gas models have a small black button per pictures I've seen. The button should "click" when pressed if it was tripped. If so, reassemble and check if the machine now heats. It the overheat didn't seem to be tripped and it still doesn't heat after pressing the reset button, then something else is at fault.

Hello--Thank you for the valuable info. The complete cycle may take 5-10 minutes @ the very most. Does that tell you something? We have not seen any fault code displayed.

We have cleaned out the grill on the left side where the bucket mounts. We have also cleaned out the ducting as best we could. The reason we did that was because the cycle was taking so long & clothes weren't as dry as they should be.

My husband is somewhat knowledgable with appliances & he is an electrician, so maybe he can do this as you explained it.

Again, thanks for the info!

So, if you set the machine for a longer timed dry, such as 40 or 80 minutes, it still shuts off in 5 mins? Or does it run for the set time but just doesn't heat?

If you turn the dryer on and check outside the house at the exhaust outlet, there's a strong flow of air? In regards to cleaning the exhaust ducting, it must be checked and cleaned the entire distance from behind the dryer, through your wall, attic, basement, or whatever is the path it takes to outside the house. However, an obstructed exhaust should trigger a fault code on the machine. It senses the condition by monitoring if the auto-resetting overheat thermostat triggers. Since this one auto-resets, the fault will be recorded but the dryer will continue to run and heat. The manual-reset overheat thermostat triggers at a higher temp and doesn't auto-reset for safety purposes. The dryer will run but not heat.

The other possibility that comes to mind in regards to the very short run-time on auto-sense leaving wet clothes is if the wires to the sensor bars have come loose. You mention above that you've cleaned the outlet grill on left side of the drum. If you removed the grill, those wires could have come loose from the bars, causing the moisture sensor to not work. But, this shouldn't have any impact on timed drying.