2007 Hummer H3 Owner's Manual - Page 106

Automatic Transmission Operation PARK (P): This position locks your rear wheels. It is the best position to use when you start the engine because your vehicle cannot move easily. {CAUTION: The automatic transmission has a shift lever on the console. It features an electronic shift position indicator within the instrument cluster. This display must be powered anytime the shift lever is capable of being moved out of PARK (P). This means that if your key is turned off, but not in LOCK, there will be a small current drain on your battery which could discharge your battery over a period of time. If you need to leave your key in the ignition but not in LOCK for an extended period, it is recommended that you disconnect the battery cable from the battery to prevent discharging your battery. There are several different positions for your shift lever. 106 It is dangerous to get out of your vehicle if the shift lever is not fully in PARK (P) with the parking brake firmly set. Your vehicle can roll. Do not leave your vehicle when the engine is running unless you have to. If you have left the engine running, the vehicle can move suddenly. You or others could be injured. To be sure your vehicle will not move, even when you are on fairly level ground, always set your parking brake and move the shift lever to PARK (P). See Shifting Into Park (P) (Automatic Transmission) on page 117. If you are pulling a trailer, see Towing a Trailer on page 297.