WARNING: This page is about a different car, the 2006 GMC Sierra and 2006 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Power, Ground, Serial Data, and MIL Indicator
Courtesy of GENERAL MOTORS CORP.
Fig 2: Indicators, Water in Fuel Sensor, Engine Oil Level Switch, and Washer Fluid Level Sensor