2002 GMC Sonoma Owner's Manual - Page 432

Starter Switch Check CAUTION: When you are doing this check, the vehicle could move suddenly. If it does, you or others could be injured. Follow the steps below. 1. Before you start, be sure you have enough room around the vehicle. 2. Firmly apply both the parking brake and the regular brake. See "Parking Brake" in the Index if necessary. Do not use the accelerator pedal, and be ready to turn off the engine immediately if it starts. 3. On automatic transmission vehicles, try to start the engine in each gear. The starter should work only in PARK (P) or NEUTRAL (N). If the starter works in any other position, your vehicle needs service. On manual transmission vehicles, put the shift lever in NEUTRAL (N), push the clutch down halfway and try to start the engine. The starter should work only when the clutch is pushed down all the way to the floor. If the starter works when the clutch isn't pushed all the way down, your vehicle needs service. 7-48