The Kenmore microwave will not function if the door is ajar, even if the door looks closed but is not latched firmly. Open the door and then shut it until a latch is heard.
If necessary, clean the gasket on the door with a clean cloth to remove any debris that may be keeping the door from shutting properly.
Program in Progress
Another reason why the light might be on but the microwave will not operate when keys are pressed is that a selection already was made but not started. Press "Stop/Clear" twice to cancel any pre-selected cooking programs and to reset the control pad.
Alternatively, if a cooking process was stopped unexpectedly, the light may be on but the microwave will not function. Press "Stop/Clear" twice to cancel or "Start" to resume cooking.
There may not be adequate power for the microwave to operate as expected if there is partial operation of the unit. Check to see if other appliances are connected to the same outlet.
If so, move the other appliances to another outlet and do not use extension cords with the microwave oven. Push the power cord firmly into the electrical outlet and make sure the wall switch is turned on, if the outlet is controlled by a switch.
Occasionally, a microwave may need to be reset due to a power failure or outage. Press "Stop/Cancel" twice and unplug the microwave.
Wait several minutes before restoring power and making a new cooking selection. If the problem persists, contact Kenmore or another service professional for assistance.