What are the 2003 chevy silverado ground wire locations?

The 2003 Chevrolet Silverado has a huge number of ground wires, but You likely won't need most of them. In total, You're looking at upwards of 35 or 40 ground wires. If You're looking for a ground, there's a good chance You'll need an engine ground; luckily, the number of those is much more manageable. You'll find them from the block to the firewall, from the block to the core support, and from the block to the subframe. You may find them at different angles and locations, but You'll typically want to inspect for any damage. A broken ground is usually quite conspicuous; look for "shorted" or damaged wires. Also inspect each end for corrosion, and be sure to clean the area with a corrosion inhibitor before replacement, if that's Your end goal.