How To Test the Lid Switch
The lid switch ensures that the lid is closed before enabling the machine to spin or agitate. This feature was added after serious injuries resulted from people reaching into an operating washing machine. For this reason, the lid switch should never be bypassed.
Aside from electrical problems, the switch may suffer from a mechanical problem. The lid may have a striker which depresses the switch when the lid is closed. Make sure the striker is functioning and aligned with the hole over the switch. Inspect the switch and make sure the metal strip is not bent out of position (if present). If your switch uses a mercury switch, make sure the mercury envelops the internal contacts when it is in the closed lid position. Your design may differ, so inspect it for proper operation before proceeding to the electrical testing.
There are two primary types of lid switches. One type on which you can directly test the terminals on the switch and another style where you have to test it at the wiring harness. In either case the method for testing the switch is the same. If a wiring harness is used, separate the two pieces of the harness and test the side of the harness that connects to the switch.
Test the switch for continuity using a multitester. Set the multitester to the ohms setting X1. Place a probe on each terminal. The multitester should display a reading of infinity. Depress the button on the lid switch and the reading should change from a reading of infinity to roughly zero. If it does not pass both of these tests, the switch should be replaced.
Some lid switches also have a fuse, you can visually inspect the fuse or test it for continuity with a multitester. If the fuse is bad, replace it with one of the same rating.