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Home >> Hummer >> 2008 >> H2 4D Utility Pickup >> Repair and Diagnosis (Single Page) >> Body & Frame >> Ignition Switch/Steering Lock >> Wiring Systems And Power Management - Introduction >> Description and Operation >> Power Mode Description and Operation >> Serial Data Power Mode Master >> Relay Controlled Power Mode
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Relay Controlled Power Mode

The body control module (BCM) uses the discrete ignition switch inputs Run/Crank Ignition 1 Voltage, Accessory Voltage, and Ignition 1 Voltage, to distinguish the correct power mode. The BCM, after determining the desired power mode, will activate the appropriate relays for that power mode.

The RAP relay remains on for a timed period after the Ignition key is removed. Refer to Retained Accessory Power (RAP) Description and Operation  for more information on the retained accessory power (RAP) function.