Automatic Fan running continuously

GE Spacemaker
Model # JVM1340

The automatic fan runs continuously and no cooking functions will work. I can, however, turn the vent fan on & off. Unplugging the microwave for over 24 hours had no effect (wishful thinking … I was hoping it would "reboot" itself). Any ideas on what might be causing automatic fan to think it needs to always be running?

Thanks much!

Sounds like the problem is a bad control board because the cooling fan operates by this board. If you need the right part number for the control board then post the rest of the model number.

Gene.