Why does my GE microwave turn on when I close the door?

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Many people go onto appliance forums seeking advice for microwave issues. One of the more prominent issues seems to be a microwave fan that keeps running even when the door is closed. 

There is one primary reason why a GE microwave fan keeps running when the door is closed, according to all the appliance experts. The door interlock switch is faulty. The one solid fix you can do to resolve the problem is to replace the switch. 

The Fan Problem

People list two types of fan problems. Problem number one is the microwave fan runs when the door is open. Problem number two is it runs after the oven has finished cooking and the door is closed. 

Both problems are related to the same issue of a faulty door interlock switch. It could also be the door assembly or latch. You should inspect both. 

Microwaves are designed so that the door latch hits a switch when it’s closed. The connection allows the microwave to receive power when it’s activated. 

However, things can get a bit more complicated because there are two fans. People can get confused about which fan is running. 

Read: How To Vent A Microwave On An Interior Wall

Tale of Two Fans

Many microwaves have two fans, depending on the model. It has a vent fan for removing heat or steam coming up from the stove below a built-in microwave. It also has a cooling fan to keep high voltage components at the right temperature.

The cooling fan is on the right-side panel. Most people have issues with the cooling fan. 

How the System Works?

The fan motor is located under the oven lamp. There are three-door switches. The fan motor will run if the bottom switch, called the primary interlock switch, and the lamp relay located on the control board is closed. 

The primary interlock switch should be open when the microwave door is opened, removing power from the cooling fan. So, the switch must be bad if that isn’t happening. It is remaining closed all the time. 

That means the lamp relay closes to turn on both the interior light and the cooling fan circuit when the door opens. Normally, it just turns on the light because the primary interlock switch is open, preventing the lamp relay from giving power to the cooling fan. 

Read: Microwave Blown Fuse Symptoms

A Touchy Issue

One microwave owner said how his fan worked depended on where he touched the door. He said the fan started when he put pressure on the lower part of the door and none of the controls worked. 

He also said if he closed the door with his hand near the handle’s top, and put pressure on the top part of the door, the fan doesn’t start. All controls worked. 

The problem remained the same. He needed to replace the switch. While all three should be replaced, other advice was to also look at the door itself or the door switch mount. A loose door or mount could affect connectively between the switch and the door latch assembly. 

Read: Top Reasons Why Microwave Is Not Heating

The Door Latch Assembly

The door latch is what connects to the door switch to activate the microwave. It could be weak or loose and not in the right place after you open the door. This could cause some issues but typically isn’t the main problem. 

The main problem in these types of cases will always be the door switch, specifically the lower door switch. 

What to Do?

The first thing to do is to inspect and clean your door switches. Looking at them may give you a hint if they are bad. Door switches, like anything else in your microwave, can get gummed up with grease, food debris, and grime. 

Most people don’t think to wipe that part of the door when they clean their microwave, so it can get messy. Take some water, mild soap, and a sponge and clean them to see if that helps. 

How Much Does It Cost to Replace a Door Switch?

Door switches are selling for under $10 on Amazon. However, the official answer is that microwave door switch repairs have an average cost of between $50 and $100. That also includes labor. 

It only takes about an hour to replace a door switch if you know what you are doing, so it’s considered an easy and cheap repair. 

Read: 5 Possible Issues When Microwave Turntable Is Not Turning

Instructions for Replacing a Door Switch

Some could replace a door switch as a DIY project. Many said they have done it easily. However, repairing a microwave is a risk of injury or death if you don’t know what you’re doing. 

Generally, the door switch isn’t a piece that has a high risk of injury. Be sure to unplug the microwave before you try to disassemble anything. Only deal with the door switch. The capacitor can hold up to 4,000 volts even unplugged so you shouldn’t try to repair anything on the inside. 

Here are the steps to replace the door switch. 

Taking Out the Old Switch

• Open the microwave door and remove the screws holding the grill in place.
• Move the grill to the left. It should release.
• There is a screw on the left that holds the control panel. Remove it.
• There is a screw behind the panel. Loosen it.
• Detach the panel by lifting and pulling it forward.
• You should see the screws that hold the switch assembly. Remove them.
• Hold down the release tab and the actuator so the switch you want to replace detaches.
• There is a wire connector that needs to be disconnected to release the old switch.

Installing the New Switch

• First, connect it to the wire connector.
• Put the new switch in the assembly and snap it so it fits.
• Align the switch on the frame so you can replace the screws to secure it.
• Put the control panel back into place.
• Tighten the screw that goes behind the panel.
• Replace the screw you took out from the left side
• Slide the grill back in and tighten the screws. 

You can plug the cord back in and use the microwave now that all this is done. It’s good to test it first. 

How to Test a Microwave Program?

Fill two large cups with room temperature tap water. Put them in the microwave and heat for about two minutes. Test the temperature of the water in both cups when cooking is done. Water should be boiling in both cups. 

Since it was the fan giving you issues, open and close the door a couple of times to make sure the fan and light operate normally. 

How many door switches are in a GE microwave?

There are three switches in a GE microwave. You can see the three switches when you gently wiggle the latching panel and lift it. Pull it towards you to see the switches. Each switch has a small black switch on it. 

Read: GE Microwave Keypad Shorted – How To Fix It?

How do you know you have a failed door switch?

Once you can see the switches, you can feel each with your finger or a screwdriver to see if one appears to be stuck or not clicking. Most people recommend going ahead and replacing all three while you are replacing one so you don’t have to do another replacement soon. 

It is believed that when one goes out, the others will likely go out soon afterward.

Read: 5 Reasons Why Microwave Is Sparking Inside

How do you test a door switch?

Those who want to be certain of whether a switch is good or not can use a multimeter to test them. You will need to remove the switch to test with a probe. 

You move the dial to the lowest setting for resistance. There are three terminals on a door switch. They are common, open, and closed terminals. You will want to put the black probe on the common terminal and the red probe on the open terminal.

Move the switch down and see if the display shows continuity. Do the test again by putting the red probe on the closed switch.

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