Power Ground (PWR GND)
WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2005 Mercury Sable, 2005 Mercury Mountaineer, 2005 Mercury Monterey, 2005 Mercury Montego, and 2005 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.
The PWR GND circuit(s) is directly connected to the battery negative terminal. PWR GND provides a return path for the PCM VPWR circuits.