Pulled the oven (double convection) out of the wall, removed the back cover. Found the sensor connector had some grease in it. Disconnected the sensor, removed it from inside the lower oven. Since the new sensor has a different connector, cut off the connectors on both sides and spliced the wires together. Before closing the oven, checked that the lower oven would work. It did just like new. reassembled the oven and put it back in the wall. Just in time for Christmas dinner, we now how two ovens that work perfectly.