Microwave displays F3 and will not start; often associated with sensor cooking modes.

Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Shorted cavity temperature sensor, Shorted humidity sensor, Damaged sensor wiring harness

How to Fix / Troubleshooting

Safety first: Unplug the microwave before inspection.

Clean interior and sensor area: Grease or moisture can cause sensor issues. Wipe down the cavity and sensor grill.
Power reset: Unplug for 10 minutes, then test.
Inspect sensor wiring:
- Remove the outer cabinet.
- Locate the sensor(s) and follow the harness to the control board.
- Check for pinched, melted, or shorted wires.

If F3 persists, replace the affected sensor module. If unsure which sensor is used on your model, consult the parts diagram for your specific Black+Decker microwave.

Repair Difficulty

Medium 3/5

Required Part

Cavity Temperature Sensor or Humidity Sensor

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