Diagnosis
The membrane switch panel (the touchpad) is failing. Moisture, wear, or a faulty connection causes this.
How to Fix It
Unplug the dryer for one minute. This resets the control board. Plug it back in. Test. If still unresponsive, the user interface panel (part # 300753) needs replacement. It's the entire touchpad and display assembly.
IF THAT DIDN't WORK Rarely, the main control board behind the panel has a faulty connection. Re-seat the ribbon cable connecting the touchpad to the main board when you replace the panel.
Heads Up
Do not use liquid cleaners on the touchpad. It seeps in and ruins the contacts. Wipe with a dry cloth only.