2003 GMC Sierra 1500 Pickup Owner's Manual - Page 92

At times you may notice a decrease in range. This is normal for any remote keyless entry system. If the transmitter does not work or if you have to stand closer to your vehicle for the transmitter to work, try this: Check the distance. You may be too far from your vehicle. You may need to stand closer during rainy or snowy weather. Check the location. Other vehicles or objects may be blocking the signal. Take a few steps to the left or right, hold the transmitter higher, and try again. Check to determine if battery replacement or resynchronization is necessary. See "Battery Replacement" and "Resynchronization" under Remote Keyless Entry System Operation on page 2-5. If you are still having trouble, see your dealer or a qualified technician for service. Remote Keyless Entry System Operation If your vehicle has this feature, you can lock and unlock your doors from about 3 feet (1 rn) up to 30 feet (9 m) away using the remote keyless entry transmitter supplied with your vehicle. UNLOCK: Pressing this button once will unlock the driver's door. The parking lamps will flash and the interior lights will come on. The ground illumination lamps will come on. Pressing UNLOCK again within three seconds will cause the remaining doors to unlock. The parking lamps will flash and the interior lights will come on. LOCK: Pressing this button once will lock all of the doors. Wait one second, then press LOCK again and the horn will chirp. Operating the keyless entry transmitter may interact with the theft-deterrent system. See Content Theft-Deterrent on page 2-18. Remote Alarm When the panic button with the horn symbol on the keyless entry transmitter is pressed, the horn will sound and the headlamps and taillamps will flash for up to 30 seconds. This can be turned off by pressing the panic button again, waiting for 30 seconds, or starting the vehicle. 2-5