When you hit Start, does the oven lamp come on but not the fan or turntable?
That would be a problem with the secondary (bottom) door interlock switch or its mount.
This is usually caused by either a bad door switch, a loose door switch mount, or occasionally a problem on the control panel.
Even though a door switch clicks, it may still be bad inside. Its continuity must be checked.
switch or mount trouble can be caused by slamming the door or by
opening the door while it's cooking without hitting the Stop pad first.
are plastic mounts inside the microwave which hold the door switches
and onto which the door latches lock when you close the door.
The screws on these mounts may be loose. If they get too loose, the switches will not be activated properly.
it's a broken tab on the switch holder, allowing the switch to rotate
just out of position. This tab
can be hard to see, since it is under the bottom edge of the switch.
One test that sometimes helps is to gently lift up (and/or push down) on the door or
handle as you try to start it. If it works or tries to work, then it's
a door switch mount or door alignment issue.
you or someone you know decide to look into it, we have critical
information on safety, disassembly and door switches at our site, and
our link is at our listing here on FixYa:
You can probably find exploded views and order parts by entering your model number here at the Sears parts site
The best place to order Sharp parts is Tritronics
If you think the problem is on the control panel, we repair these nationwide by mail for $39.95 postpaid in most cases.We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.