Shorts to Ground
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.
Measure the harness resistance between the suspect circuit at the harness connector and a reliable ground (B-, chassis gnd, or PWR GND at the PCM breakout box, if available). The resistance must be greater than 10,000 ohms.