TP86BF5BB Microwave Door Switch — Diagnose & Replace the Door Interlock
Need the replacement part? Search your model number at for guaranteed fit and fast free shipping.
Understanding the Problem
The door switch (interlock) in a microwave is a safety device that prevents the oven from running when the door is open. If a door switch fails, the microwave may not start at all, may stop mid-cycle, may run only when the door is held a certain way, or — in rare cases of miswiring/damage — could run with the door open, which is dangerous. Symptoms usually appear suddenly after the door is closed or after the door has been jostled repeatedly. Most failures are caused by worn or burned switch contacts, mechanical damage to the switch actuators or door latch, or broken/loose wiring/connectors. Before replacing any part, always unplug the microwave and discharge the high-voltage capacitor; internal components carry lethal voltages even when unplugged. If you’re not comfortable with high-voltage electronics, contact a qualified appliance technician.
Common Symptoms
Microwave won’t start or starts only when door is pressed a certain way; stops during cycle; no keypad response after door closure; visible burning or melted plastic near the door latch area.
Common Causes
- Worn or burnt switch contacts from arcing over time
- Broken or misaligned door latch/actuator preventing proper switch actuation
- Damaged wiring or corroded connectors to the interlock switch
Popular Parts That Fix This Problem
These are the most common replacement parts that fix this problem. When you're ready to order, click below to find the right part at PartsDiscount.com — just search by your appliance model number for a guaranteed fit.
Helpful Repair Tip
With the microwave unplugged and the capacitor discharged, remove the switch harness and use a multimeter set to continuity or ohms to check each switch while manually actuating it — a good switch will change continuity cleanly when pressed and released.
Frequently Asked Questions
How do I test a microwave door switch safely?
Unplug the microwave and discharge the high-voltage capacitor (if you’re experienced); remove the outer cabinet to access the switches. Disconnect the switch harness and use a multimeter on continuity/ohms. Manually press the switch actuator — continuity should change (open to closed or closed to open) cleanly with no intermittent readings. Replace switches that show no change, intermittent continuity, or visible burning. If unsure about capacitor discharge or cabinet removal, call a professional.
Can I keep using the microwave if the door switch is intermittent?
No. An intermittent or failing door interlock is a safety risk. It can cause the microwave to shut off unexpectedly during use or, in worst-case scenarios with multiple failures, allow operation with the door not fully secured. Stop using the appliance and repair or replace the faulty switch(es) before further use.
Real DIY Repair Stories
Be the first to share your repair story!
Share Your Repair Story
Your experience helps other homeowners fix their appliances. Tell us how it went!
Can't Fix It Yourself? Find a Local Technician
It's perfectly okay to call a professional. Some repairs require specialized tools, deep teardowns, or dealing with complex systems that are better left to the pros.
Find the Right Part for Your Appliance
Don't guess — search your exact appliance model number at PartsDiscount.com to find the correct OEM compatible replacement part. They offer fast free shipping, guaranteed fit, and thousands of parts in stock.
Your Free Parts Videos
Whether your dishwasher won't drain, your dryer stopped heating, or your fridge isn't cold, we've created simple repair guides for the most common appliance problems homeowners face. Each guide explains what's going wrong, the most likely causes, and which replacement parts fix the issue. When you're ready to order, we link directly to PartsDiscount.com where you can search by model number and get the right part shipped fast.