Ground Circuits
WARNING: This page does not describe the selected car, but rather 15 other vehicles, including the 2003 Hummer H2, 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 GMC Sierra, and 2003 GMC Savana. However, it is still accessible from the selected car via links, so may be relevant.
Check PCM connectors for corroded or loose connections. Repair as necessary. Disconnect PCM connectors. Using a DVOM, measure resistance between negative battery terminal and ground terminals at PCM harness connector. If resistance is more than 5 ohms, repair open in affected ground circuit. If resistance is 5 ohms or less, ground circuits are okay.