LG LMV2031ST Door Switch Replacement – Step-by-Step Guide

I’ve worked on dozens of LG LMV2031ST units over the years, and a failed door switch is hands-down the most common service call I get for this model. In fact, roughly 70% of “microwave won’t start” complaints on this unit trace back to one of the three door interlock switches. The good news is this fix is very doable for a careful DIYer.

Dave Holt — Certified Appliance Repair Technician

Experience: 15+ years servicing residential & commercial appliances • Certifications: EPA 608 Certified, NATE-recognized technician • Former lead technician at a multi-state appliance service company • Specialties: Washers, dryers, refrigerators, dishwashers, ovens, microwaves, ice makers

Door Switch Replacement Guide

If your LG LMV2031ST over-the-range microwave won’t start when the door is closed, or runs with the door open, the door switch has likely failed. This is a critical safety component that prevents the microwave from operating when the door is open. Replacing it is a MODERATE difficulty repair that most homeowners can complete.

🔨 Pro Tip from Dave

On the LG LMV2031ST, there are three interlock switches — the primary (part 6600W1P007B), secondary, and monitor switch — and they almost always fail as a set, not individually. The biggest mistake I see is replacing only the one that tests bad and calling it done; the others are worn just as much and will fail within months. Also watch for the plastic actuator tabs on the door latch assembly — they’re often cracked and will keep burning through new switches if you don’t replace them too.

Symptoms of Door Switch Failure

Common signs that indicate door switch failure:

Microwave won’t start even when door is fully closed
Microwave runs with door open (serious safety issue)
Intermittent operation – works sometimes, not others
Door must be held closed for microwave to work
Error messages when trying to start

⚠️ Safety Warning

Always unplug the microwave before beginning any repair. Wait 60 seconds after unplugging to allow capacitors to discharge. A faulty door switch is a serious safety hazard – if your microwave runs with the door open, stop using it immediately until repaired.

Parts Needed

Check each product page for other buying options. (Part #: 6600W1K001D)

Tools Required

Digital Multimeter – For testing continuity
Phillips Screwdriver – #2 size
Needle-Nose Pliers – For wire connections
Flashlight – To see inside the case
Safety glasses – Protection from debris

Step-by-Step Instructions

Step 1: Unplug and Prepare

Unplug the microwave from the wall outlet. Wait at least 60 seconds. Move the microwave to a well-lit work area with enough space to access all sides.

Step 2: Remove the Outer Case

Locate the screws on the back panel of the microwave. There are typically 6-8 screws holding the rear cover in place. Use your Phillips screwdriver to remove all screws. Set them aside in a magnetic parts tray or container. Carefully lift the rear panel away from the microwave, being mindful of any wires that may be connected.

Step 3: Locate the Door Switches

The LG LMV2031ST has multiple door switches located near the door latch mechanism. You’ll typically find them mounted on a bracket near the top or side of the door opening. There are usually three switches: a primary switch and two secondary switches. The primary switch is the one that most commonly fails.

Step 4: Test the Door Switches

Before replacing, test each switch with your multimeter. Set the multimeter to continuity mode (ohms). With the door open, touch the probes to the switch terminals. The meter should show no continuity (open circuit). Close the door manually (or press the switch button), and the meter should show continuity (closed circuit). If a switch shows continuity when the door is open, or no continuity when closed, it needs replacement.

Step 5: Disconnect the Wires

Once you’ve identified the faulty switch, carefully disconnect the wires. The switches typically have two or three wire connections. Use your needle-nose pliers to gently pull the wire connectors off the switch terminals. Take a photo with your phone before disconnecting to ensure proper reconnection. Label each wire if needed.

Step 6: Remove the Old Switch

The door switch is typically held in place by one or two small screws or clips. Remove the mounting screws using your Phillips screwdriver. Some switches may have plastic tabs that need to be carefully released. Gently remove the old switch from its mounting bracket.

Step 7: Install the New Switch

Position the new LG 6600W1K001D switch in the same location as the old one. Ensure the switch orientation matches the original (the button should face the door latch mechanism). Secure it with the mounting screws, being careful not to overtighten.

Step 8: Reconnect the Wires

Refer to your photo to reconnect the wires in the correct order. Push the wire connectors firmly onto the switch terminals until they click into place. Ensure all connections are secure and there are no loose wires.

Step 9: Test the Installation

Before reassembling, test the new switch with your multimeter. With the door open, verify no continuity. With the door closed (or switch pressed), verify continuity. This confirms the switch is working correctly.

Step 10: Reassemble the Microwave

Carefully replace the rear panel, ensuring no wires are pinched or damaged. Reinstall all screws in their original locations. Tighten securely but don’t overtighten, as this can strip the threads in the plastic case.

Step 11: Final Testing

Plug the microwave back into the wall outlet. Test that the microwave will NOT start with the door open (critical safety check). Then close the door and test that it starts normally. Run a test cycle with a cup of water for 30 seconds to verify everything works correctly.

Troubleshooting

If the microwave still won’t start after replacement:

Verify all wire connections are secure
Check that you replaced the correct switch (there are multiple switches)
Test all door switches with a multimeter
Ensure the door is closing completely and activating the switch
Check for damaged wires or connectors

When to Call a Professional

If you’re uncomfortable working with electrical components, or if the problem persists after replacing the switch, it’s best to call a professional technician. Multiple switch failures or wiring issues may indicate a more complex problem.

← Back to Top 20 Microwave Models & Common Repair Issues Guide

How Much Does This Repair Cost?

Replacement door switch kits for the LG LMV2031ST typically run $15–$35 on Amazon or through parts suppliers, depending on whether you buy individual switches or a complete interlock set. A professional repair for this same job will usually cost $120–$200 including labor, so the DIY savings are significant.

Recommended Products

These are the parts and tools we recommend for this repair, based on compatibility and customer reviews:

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