This step shows how to test the switch, which will require a multimeter. If you aren't familiar with how to use one, here is a guide that will help you.

Insert the multimeter's probes into the two outermost sockets on the switch connector and test continuity and open on the door switch.

When the button on the switch is not pushed, the meter should indicate OL.

When the button is pushed with the probes in the same place, the meter should read less than 1 Ω.

If either of these readings is wrong, especially with the button pressed, replace the switch.