2003 GMC Yukon Owner's Manual - Page 299

4: In this mode all four wheels will help steer the vehicle. If you want to use 4, and your vehicle is not in this mode, press the button, until the 4 indicator, located to the right of the 4 Wheel Steer button, comes on and stays on. If the 4 indicator is flashing you will have to center the steering wheel by turning it to the left or right. The switch is located on the instrument panel. 2: In this mode the vehicle will operate like any other vehicle with two wheel steering. If you want to use 2 wheel steer mode and your vehicle is not in this mode, press the button until the 2 indicator, located to the right of the 4 Wheel Steer button, lights up. If the 2 indicator is flashing you will have to center the steering wheel by turning it to the left or right. Your vehicle will return to 2 when the transmission is shifted into NEUTRAL, for example when entering a car wash. If you want to use tire chains, the vehicle needs to be in 2 wheel steer mode. For more information see Tire Chains on page 5-68. Slower Speeds (below 40 m.p.h./ 64 km/h ) At slower speeds the front and rear wheels will turn in opposite directions. This helps the vehicle make tighter turns, such as during parking, cornering and turning into tight spaces. 4-17