(A)風扇繼電器係常閉式(Normal closed) (B)在引擎低溫時,溫度開關(Thermostaticswitch)閉合形成風扇繼電器線圈搭鐵通路 (C)系統正常且供電中,拆開溫度開關(Thermostatic switch)接頭風扇應即刻運轉 (D)溫度開關(Thermostatic switch)故障時風扇即無法運轉 。