Where is the 4x4 module on a 2004 Chevy Silverado?

The 2004 Chevy Silverado doesn't have a single "4x4 module" in the way some vehicles might have a dedicated control module for just the 4WD system. Instead, the 4x4 system's functionality is controlled and monitored by several components and their associated circuitry, primarily within the body control module (BCM) and potentially the transfer case control module (if equipped).

Therefore, there isn't one specific location to point to. The BCM is typically located under the dash, while a separate transfer case control module (if present) would be closer to the transfer case itself, likely under the truck.

To troubleshoot 4x4 issues, a mechanic would use a scan tool to read diagnostic trouble codes (DTCs) from the BCM and other relevant modules to pinpoint the problem. Simply looking for a physical "4x4 module" won't be helpful.