Over-the-range microwave mounted above a stainless electric range
Generic photo: Curtis Adams · Pexels License

Over-the-range microwave vent fan or cooktop light not working

Start with bulbs, grease filters and the fan's thermal protection. A fan that runs by itself is often a stuck relay on the control board or the board's automatic hot-cooktop protection reacting to heat below. Fan motor and relay tests are internal: high-voltage warning applies.

Single source ~45 min moderateBrands: All

Before you start

  • Turn off the breaker for the OTR circuit before removing bulbs, covers or the top grille
  • DANGER: the high-voltage capacitor can hold a lethal charge even when unplugged; inexperienced users should not open the cabinet
  • Trained techs: discharge and verify 0 V before testing the fan motor or control relays

Diagnostic steps

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OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.

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Over-the-range microwave vent fan or cooktop light not working · OnCall Tech