Testing for higher amperage IOD must be performed first to prevent damage to most milliamp meters.

  • If the vehicle is equipped with a Security Alarm disconnect the Security Alarm relay that is located in the relay center under the glove box.
  • Verify that all electrical accessories are OFF. Turn off all lights, remove ignition key, and close all doors. If the vehicle is equipped with electronic accessories (illuminated entry, high line radio), allow the systems to automatically shut off (time out), up to 3 minutes.
  • After determining that the underhood lamp is operating properly then disconnect bulb.
  • Disconnect negative cable from battery.
  • Connect a typical 12 volt test light (low wattage bulb) between the negative cable clamp and the battery negative terminal. If equipped with security alarm, cycle the key in the door to turn off the flashing lights. Make sure that the doors remain closed so that illuminated entry is not activated. The test light may light brightly for up to 3 minutes or may not light at all (depending on the electrical equipment). The term brightly being used throughout the following tests, implies the brightness of the test light will be the same as if it were connected across the battery.
    The test light must be securely clamped to the negative cable and battery terminal. If the test light becomes disconnected during any of the IOD test, the electronic timer function will be activated and all tests must be repeated. If the ammeter circuit is broken the Security alarm module will turn on parking lamps.


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