Need help with my double oven. The top oven will not heat on bake, broil or convection. The fan comes on, but it won't heat and stays at 135 degrees. The bottom unit works fine. I tried the reset switch, but no luck.

I don't believe it's the elements because they would have all had to go bad at the same time.

The crazy thing is it stopped working one day and the next day it worked fine. Two days later, it's broke again.

Any suggestions?