Check the continuity between the switch terminals.
If the test results are negative, replace the switch.
1. Checking the operation of the switch.
a) battery to terminals 17(+) and 14(-) of the switch.
b) Connect the voltmeter to terminals 217(+) and 14(-) of the switch.
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Turn on the ignition and move the switch to. Connect the INT position: the device should register the battery voltage.
c) Move the voltmeter probe from terminal 14 to terminal 20, then to terminal 17 and immediately back to terminal 14. The device should register zero voltage within 3-5 seconds and return to registering the original voltage.
If the test results are negative, replace the switch.