Is Your Microwave Staying On? What’s Causing It and Why You Should Act Fast

Is Your Microwave Staying On? What’s Causing It and Why You Should Act Fast

Why Is My Microwave Always On?

Causes and the Dangers of Microwaves That Stay Running

Microwaves are essential kitchen appliances, but when one starts acting oddly—like staying on even after the timer ends—it’s time to take a closer look. A microwave that continues to run poses both safety and performance issues. Here’s what might be causing it and why you should address the problem promptly.

Common Causes

1. Faulty Door Switch

The most frequent reason for a microwave that won’t shut off is a defective door switch. Microwaves are built with one or more door switches that signal the control board to stop operation once the door is opened. If one of these switches is stuck or broken, the microwave may think the door is still closed—and keep running.

2. Control Board Malfunction

A malfunctioning control board can also be to blame. The control board acts as the brain of the microwave. If it sends the wrong signal or doesn’t respond properly when the timer ends, it may continue supplying power to the unit.

3. Stuck Relay

Inside the microwave’s control circuitry is a relay switch that regulates power to components like the magnetron. If this relay gets stuck in the “on” position, the microwave can continue running regardless of the timer or door status.

4. Timer or Display Issues

Sometimes the timer or digital display may be showing an incorrect countdown or may have frozen. The microwave could appear off but still be emitting radiation or running the fan and light internally.

Why This Is Dangerous

  • Continuous Radiation Exposure
    Although low, microwave radiation can cause serious safety risks if emitted over a prolonged time, especially if the door isn’t sealing properly.

  • Fire Risk
    A microwave that runs continuously without food or with flammable materials inside can overheat and catch fire.

  • Electrical Waste
    Beyond the danger, a constantly running microwave is also a drain on your electricity bill and shortens the lifespan of internal parts like the magnetron.

What Should You Do?

If your microwave stays on:

  • Unplug it immediately to stop further operation.

  • Do not attempt repairs yourself unless you are trained—microwaves contain high-voltage components even when unplugged.

  • Contact a certified technician to diagnose and fix the issue safely.

At PRS Parts Inc., we carry OEM replacement parts like door switches, control boards, and relays for most major brands. Plus, our certified technicians can help you diagnose the issue over the phone or in-store.

Visit PRS Parts Inc. at 540 Lagoon Dr. for authentic appliance replacement parts and expert repair assistance. We’re here to help you fix it right—the first time. Service with the spirit of aloha.

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