Fusible Links
WARNING: This page does not describe the selected car, but rather 24 other vehicles, including the 2004 GMC Yukon XL, 2004 GMC Yukon, 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, and 2004 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
For information on fusible links and repairing them, refer to illustration. See Fig 1.