Hood Sensor/Switch (For Alarm): Testing and Inspection

The diagnosis found here addresses an inoperative hood ajar switch. If the problem being diagnosed is related to hood ajar switch accuracy be certain to confirm that the problem is not an improperly adjusted hood ajar switch. If no hood ajar switch adjustment problem is found, the following procedure will help to locate a short or open in the hood ajar switch circuit. Refer to the appropriate wiring information.

WARNING: ON VEHICLES EQUIPPED WITH AIRBAGS, DISABLE THE AIRBAG SYSTEM BEFORE ATTEMPTING ANY STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. DISCONNECT AND ISOLATE THE BATTERY NEGATIVE (GROUND) CABLE, THEN WAIT TWO MINUTES FOR THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE BEFORE PERFORMING FURTHER DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.

1. Disconnect and isolate the battery negative cable. Disconnect the hood ajar switch. Check for continuity between the harness ground circuit a good ground. There should be continuity. If OK, go to Step 2. If not OK, repair the open ground circuit to ground.
2. Check for continuity between the two terminals of the hood ajar switch. There should be continuity with the switch plunger extended, and no continuity with the switch plunger depressed. If OK, go to Step 3. If not OK, replace the faulty hood ajar switch.
3. Disconnect the instrument panel wire harness connector from the Body Control Module (BCM). Check for continuity between the hood ajar switch sense circuit of the hood ajar switch and a good ground. There should be no continuity. If OK, go to Step 4. If not OK, repair the shorted hood ajar switch sense circuit between the hood ajar switch and the BCM.
4. Check for continuity between the hood ajar switch sense circuit and the instrument panel wire harness connector for the BCM. There should be continuity. If OK, proceed to diagnosis of the Vehicle Theft Security System (VTSS). (Refer to ELECTRICAL/VEHICLE THEFT SECURITY - DIAGNOSIS AND TESTING). If not OK, repair the open hood ajar switch sense circuit between the hood ajar switch and the BCM.