Update a lightswitch field in Craft CMS 2
If it's only one single field and you want to bypass all Craft validations for required fields you can change the value directly in your database using Yii commands and the update function

function update($table, $columns, $conditions='', $params=array())


$command = craft()-&gt;db-&gt;createCommand();
$command-&gt;update('craft_content', 
    array(
        'field_yourLightSwitchField' =&gt; 1,
    ), 
    'elementId=:id', array(':id'=&gt;1)
);


If you have a multilocale setup you need to include the condition for the correct locale as well