2003 GMC Sierra 1500 Pickup Owner's Manual - Page 203

Cruise Control Light , Tow/HauI Mode Light This light is displayed when the towlhaul mode has been activated. The cruise light comes on whenever you set your cruise control. See "Cruise Control" under Turn SignaVMultifunction Lever on page3-7. Four-Wheel-Drive Light The four-wheel drive indicator will light up when you shift a manual transfer case into four-wheel drive and the front axle engages. For more information, see Towing a Trailer on page 4-66. Overdrive Disable This light will illuminate when the overdrive disable feature is activated. The overdrive disable feature will prevent your vehicle from shifting into fifth (5) gear. Some delay between shifting and the indicator's lighting is normal. See Four-wheel Drive on page 2-35 for more information. 3-4%