You are correct about that microwave having a recall that involved the addition of a thermal fuse kit added to the top stirrer motor. That kit should have already been installed in that microwave. If it has, there should be a green dot beside the model/serial number plate as shown in the image below. If you do not see that green dot and that kit has apparently not been installed in that model, then I recommend that you call Sears at 1-800-469-4663 (1-800-4MY-HOME) for service (you can also schedule service online through this link:
Sears Home Services
). You will normally need to agree to pay for that service call so that the technician can visit your home and examine the microwave. If that kit was never installed in that microwave then you should not normally be charged for that service. If the kit was installed but that green sticker fell off then you will probably be charged for the service call.
The part number for the kit on that microwave is 8184461 but it is not available for purchase by an individual other than a Sears or other authorized technician. It is intended only for installation by a factory trained and authorized technician to repair that safety problem with the microwave. That is probably why you have had problems getting information about that part number. I do not recommend that you try to fix this problem yourself. I recommend that you
unplug the microwave
and not use it until it is properly repaired.
I understand your concern about the safety of this microwave without the kit installed. That is why I recommend that you not use the microwave until it is serviced by a technician.
I hope that this is the information that you were seeking. If you need more help, reply with additional details and we will try to assist you further.