Circuit/System Description

The engine control module (ECM) monitors the voltage input of the hood open switch signal circuit and the hood open closed switch signal circuit. With the hood open, the hood ajar portion of the switch is closed, grounding the hood ajar switch signal circuit from the ECM, and the hood closed portion of the switch is open. With the hood closed, the hood closed portion of the switch is closed, grounding the hood closed switch signal circuit from the ECM, and the hood ajar portion of the switch is open. During proper operation, the two separate voltage signals at the ECM should never be at the same voltage.