Page 79 of the owner manual states...
<HR style="BACKGROUND-COLOR: #dddddd; COLOR: #dddddd" SIZE=1><!-- / icon and title --><!-- message -->Perimeter lighting feature (if equipped)
The perimeter lighting feature illuminates the exterior of the vehicle in
order to provide better visibility to the user while he or she approaches
and enters the vehicle.
The perimeter lighting feature activates the head lamps, park lamps and
side marker lamps when:
• the user activates an unlock feature, using either the remote keyless
transmitter or the keypad, or
• when the vehicle is unlocked using the driver’s door key lock cylinder.
The perimeter lighting feature will turn off if:
• the vehicle is locked using the remote entry transmitter, or
• the ignition is turned to the 3 (ON) position, or
• after 25 seconds of illumination.
Enabling/disabling the perimeter lighting feature
Your vehicle comes with the perimeter lighting feature enabled. You may
enable/disable this feature by having your vehicle serviced by your
authorized dealer.
You may also perform the following power door lock sequence to
enable/disable the perimeter lamps feature. All vehicle doors must be
closed before beginning the procedure. You must complete Steps 1–3
within 30 seconds, or the procedure will have to be repeated.
1. Turn the ignition to the 3 (ON) position, then press the unlock control
three times.
2. Turn the ignition to the 1 (OFF) position, then press the unlock control
three times.
3. Turn the ignition to the 3 (ON) position; the horn will chirp to
indicate the driver configuration mode has been activated.
Activating or deactivating the perimeter lighting once in program mode is
accomplished by:
• pressing the trim panel power door unlock control twice within
five seconds.
At this point, perimeter lighting will be activated if it was previously
deactivated, and deactivated if it was previously activated. Confirmation
of perimeter lighting being activated is provided by a short horn chirp
followed by a long horn sound; Confirmation of perimeter lighting being
deactivated is provided by a short horn chirp only.
Exiting the program mode is accomplished by turning the ignition to any
position other than the 3 (ON) position, or two minutes elapsing since
the program mode was entered.
Norm I think a good reason for it is to find my car at night lol (without sounding the horn)