Parasitic Draw Testing

System Description


Ford\'s system is called the \"Battery Saver Relay\" system where as GM uses the term \"Inadvertent Power Relay\" to identify their system. For this discussion we will focus on the Ford system. The GM system is similar in design and function. The Battery Saver Relay System uses a relay with normally open contacts to interrupt battery feed to accessory circuits. The GEM (generic electronic module) controls the relay coil by energizing the coil upon key off. Ground is supplied to relay coil for 40 to 60 min. at shutdown. A timer function resides within GEM which allows the relay to remain energized for up to one hour to provide power to many of the battery fed accessory circuits. Operating many of the accessories, such as the door ajar switches prior to timeout resets the timer. The relay coil current draw is approximately 210ma. (similar to the draw caused by a glove box lamp).

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