Buick Century 2003 Owner's Manual page 76

Programmable Modes
Your vehicle can be programmed to one of the following
modes.
Mode 1: No Verification
Mode 2: Horn Chirp only
Mode 3: Headlamps Flash only
Mode 4: Horn Chirp and Headlamps Flash
The vehicle was originally programmed to Mode 3. The
mode may have been changed since then. To
determine the current mode, or to change the mode, do
the following:
1. Close all doors and turn the ignition key to RUN.
2. Press and hold the power door lock switch in
the lock position.
3. While holding the door lock switch in the lock
position, press and release the remote keyless entry
transmitter LOCK button. This will start the
customization mode. While in the customization
2-6
mode, the feature will sound the number of chimes
corresponding to the current lock mode. If you
do not wish to change the current mode, you can
either exit the programming mode by following
the instructions listed here or program the
next feature available on your vehicle.
4. Each additional press of the remote keyless entry
transmitter LOCK button will cause your vehicle to
advance the lock mode by one, starting from
the current lock mode.
5. If cycled beyond Mode 4, the vehicle will enter
Mode 1. When the door lock switch is released,
the vehicle will remain in the most recent lock mode.
The mode you selected is now set. You can either exit
the programming mode by following the previous
instructions or program the next feature available on
your vehicle.
Disconnecting the vehicle's battery for up to a year will
not change the programmed mode for the lock and
unlock security feedback features.