Some switches also contain a rheostat to control the brightness of the instrument panel lights. 一些開關也包含一個可變電阻器,控制儀錶板燈的燈光亮度。
The rheostat is operated by rotating the control knob, separating it from the push-pull action of the main lighting switch. 可變電阻器由旋轉的控制手柄操縱,與燈光總開關的推一拉的操縱是分開的。