LG Microwave Error Code F-7 — Door Sensing Switch Fault
What this means
The F-7 error code on LG microwaves indicates a problem with the door sensing (interlock) switch system. Microwaves have multiple safety switches that must confirm the door is fully closed before the magnetron can operate. When a switch fails, sticks, or sends conflicting signals, the microwave displays F-7 and refuses to start. Common causes include a worn switch, a broken or cracked door hook, or a misaligned door latch.
Alternate codes: F7
Step-by-step fix
4 stepsCheck the door hooks and closure
Open and close the microwave door firmly. Inspect the door hooks (the plastic fingers that protrude from the door edge) for cracks, chips, or breakage. They must fully engage the switch actuators in the frame.
Door hooks are made of plastic and can crack from slamming the door. Even a hairline crack can prevent full switch engagement.
Power cycle the microwave
Unplug the microwave for two minutes. Plug it back in and test. A temporary switch glitch can sometimes cause a false F-7.
If the error appears randomly, the switch contacts may be intermittent due to wear.
Test the door interlock switches
Unplug the microwave. Remove the outer cabinet. LG microwaves typically have three interlock switches. Disconnect each one and test with a multimeter. Each should toggle between open and closed when the corresponding door hook actuates it.
WARNING: Stay away from the high-voltage capacitor. Only work in the door switch area near the front of the microwave.
Replace faulty switches or door hooks
Replace any switch that doesn't toggle properly or any door hook that is cracked. Switches snap into mounting clips and are inexpensive. Reassemble and test by opening and closing the door several times.
If one switch has failed from wear, the others are the same age — consider replacing all three as a set.
When to call a professional
If all switches and door hooks test good but F-7 persists, the control board's door switch monitoring circuit may have a fault. A qualified technician should diagnose this due to high-voltage components.
Related error codes
Information compiled from manufacturer service manuals, official troubleshooting documentation, and appliance repair industry resources. This guide is for informational purposes only — always consult a qualified technician for complex repairs.
Learn more about our sourcesParts you may need
Door Interlock Switch (set of 3)
Part #3B73362F · $8–$18
If any switch fails the continuity test
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