Microwave not heating? Light on but no heat? Door not activating start button? A faulty door switch could be the issue. Don’t junk the microwave just yet – replacing the door switch is an easy fix. This step-by-step guide will walk you through how to safely repair microwave door switches in under an hour, saving the cost of a new microwave.
How Microwave Door Switches Work
Microwave door switches are activated by a plastic plunger that gets depressed when the door is closed. This completes a circuit that allows power to flow to the interior high voltage transformer, magnetron tube, and other components involved in generating microwaves.
Most microwaves have two identical interlock switches located on the latch side of the door assembly. Each switch has an actuator arm that gets pushed down when the door closes. If either switch fails, the microwave’s safety interlocks prevent the oven from running.
When the plunger is released from pressing the actuator arm, the switch opens and cuts power. The door switches are normally closed switches – closed when the door is shut, and open when the door is open.
Diagnosing a Faulty Microwave Switch
If your microwave has some but not all functions working, the most likely culprit is a bad door switch. Symptoms include:
- Microwave power doesn’t turn on
- Interior light works, but no heat
- Microwave stops cooking when door is closed
- Display works, but pushing buttons does nothing
First, check for any loose, damaged, or misaligned parts on the door latch area that could be preventing the plunger from depressing the switch actuator.
If visually everything looks normal, use a multimeter to check for continuity through the door switches with the door both open and closed. You should get continuity (beep) when closed and no continuity when open. If not, replace one or both switches.
What You’ll Need
- Standard and Phillips screwdrivers
- Needle nose pliers
- Multimeter
- Replacement switch kit (match your model)
- Protective gloves
Purchase an OEM replacement switch kit designed for your microwave brand and model. Generic universal kits may not fit right. investment in quality parts means less troubleshooting later.
Microwave Door Switch Replacement Steps
Follow these steps to safely replace faulty microwave switches:
1. Unplug Microwave
Before any work, always unplug the microwave or disconnect the power source. This prevents electric shock risk.
2. Remove Outer Casing
The door switch assembly is contained inside the outer wrap or casing. Carefully pry off or remove any screws holding the casing in place.
3. Disconnect Wiring Harness
Locate the door switch wires, usually on the right side. Gently detach the connector plugs from the switches.
4. Remove Mounting Screws
Use a Phillips head screwdriver to remove any screws holding the switch brackets to the door frame.
5. Detach and Remove Old Switches
Once screws are out, carefully maneuver the switches out from the bracket and door assembly.
6. Install New Switches
Align the new switches into position and reinsert any necessary screws. Attach wiring harness plugs to terminals.
7. Reassemble Microwave
Replace outer wrap, reconnect power, and test operation by heating a cup of water.
With the right replacement part and safety steps, even novice DIYers can succeed in fixing a broken microwave door switch. Take your time and follow instructions carefully.
Troubleshooting Tips
If the new switch doesn’t resolve the issue, recheck connections and test continuity again. Inspect the door latch, alignment and plunger to make sure the actuator arm is being fully depressed.
When to Call a Professional
While do-it-yourself microwave repair is possible, more complex issues like severe arcing or sparking, charring, damaged internal components, or a faulty magnetron tube require professional service.
If you don’t feel comfortable working with electrical safety or dismantling the microwave interior, contact an authorized service company. Continuing to run a severely damaged microwave could be a fire hazard.
Extend Your Microwave’s Lifespan
With proper care and maintenance, a microwave can provide reliable service for over 10 years. Follow good practices like:
- Keep the door and inner surfaces clean of food splatter
- Don’t run empty, which can damage the magnetron
- Ensure proper door alignment, latching and switch operation
- Ventilate the unit so it doesn’t overheat
Repairing a simple door switch is much more economical than replacing the entire appliance. However, when the oven no longer heats efficiently or needs other major repairs, purchasing a new one may be the better investment.
In Summary
Replacing worn out microwave door switches is a relatively easy fix. With basic tools and inexpensive replacement switches, you can often resolve no heat issues in under an hour.
Pay close attention to electrical safety and follow the step-by-step switch replacement procedure. Test operation carefully before regular use. With this simple repair, you can save the cost of buying a whole new microwave.