How to Change a Microwave Starter Switch

General Troubleshooting

• Before attempting to change a microwave starter switch, narrow down the cause of the problem. The two types of switches that may be responsible for a problem include the starter button that is part of the microwave's keypad and the interlock switch, which is located in the microwave's door frame and is responsible for completing the circuit that allows the microwave to operate. If you can enter cooking times and other commands from the keypad, the start button is not likely the source of the problem. Consult your owner's manual for basic troubleshooting steps or operating tips before proceeding.

Changing Interlock Switches

• A microwave oven won't start unless its interlock switch is properly engaged. The interlock switch is a safety switch that the door latch engages when closed. If the door is open, or if the switch is faulty, the microwave won't start. Replacing the switch involves unplugging the microwave and opening its housing by removing screws. Once the switch is exposed, you can unplug it from its retaining clip and replace it with a new switch.

Control Switches

• The control switches that make up a microwave's keypad are also necessary for it to start. These buttons are typically soft keys that engage electronic switches behind them. Corrosion, wear or a misaligned keypad all can prevent the start switch from working. To access the keypad, unscrew or pry off the front housing that surrounds the control panel. The keypad is usually connected by a ribbon cable, which you can unplug to remove the keys themselves. Clean out the area behind the keys and, if necessary, replace the start switch with a new set of keys before reinstalling the microwave's front housing.

Repair or Replace?

• In some cases, a problem with your microwave's starter switch may be easier and more cost-effective to fix by buying a new microwave rather than attempting to repair your current unit. The cost and availability of parts for older microwaves varies based on model and manufacturer. According to Realty Times, a typical microwave oven will last around 10 years before it needs replacement. This means that investing in repairs may not be worthwhile if you have an older microwave that is likely to experience additional problems soon.