Diagnosis
The bake or broil element has failed. This is the most common cause of a cold oven with a working display.
How to Fix It
Unplug the range. Remove the oven racks. Look at the large metal loop at the bottom of the oven cavity. That's the bake element. Check it for any visible cracks, blisters, or breaks. The broil element is at the top. Visually inspect it too. A failed element will often show physical damage. You need to test for continuity with a multimeter. Disconnect the wires from the suspect element. Set your multimeter to ohms. Touch one probe to each terminal. You should get a reading between 19-115 ohms. No reading means the element is dead. Replace it. The part numbers are 5304518461 for the bake element and 5304518462 for the broil element.
If That Didn't Work
The oven temperature sensor could be faulty. It's a thin metal rod in the back of the oven. Unplug it and test its resistance with a multimeter. At room temp, it should read around 1100 ohms. If it's open (infinite resistance) or shorted (near zero), replace sensor 5304518479.
Heads Up
Always disconnect power before touching any internal components. The elements get extremely hot in use, but are safe to handle when cold and unplugged.