I have a GE Monogram ***ZET857SBSS*** having some issues heating up on both top and bottom ovens. The bottom has good working fans (on every setting) but doesn't heat up at all. The top was working up until recently where I saw some sparks in the back by the fans and it no longer fully heats up. The fans spin only under the "convection" setting. I think there are different issues for both top and bottom.