Cadillac 2006 CTS Owner's Manual page 148

When the exterior lamp control is in AUTO and it is dark
enough outside, the DRL will turn off and the low-beam
headlamps will turn on. When it is bright enough
outside, the low-beam headlamps will go off, and the
DRL will turn back on. If you start your vehicle in a dark
garage, the automatic headlamp system will come on
immediately. Once you leave the garage, it will take
about one minute for the automatic headlamp system to
change to DRL if it is light outside. During that delay,
your instrument panel cluster may not be as bright
as usual. Make sure your instrument panel brightness
lever is in the full bright position. See Instrument
Panel Brightness on page 3-20.
If it is dark enough outside and the exterior lamp control is
off, a Headlamps Suggested message will appear on the
Driver's Information Center (DIC) display. This message
informs the driver that turning on the exterior lamps is
recommended even though the DRL are still on.
3-18
Turning the exterior lamp control to AUTO or to the
low-beam headlamp position will turn off the DRL and
cancel the Headlamps Suggested message.
If the parking lamps or the fog lamps were turned on
instead, the DRL will still turn off and the Headlamps
Suggested message will be displayed. You can turn it off
by pressing the OK button if you have the Navigation
audio system or the CLR (Clear) button if you have the
base audio system.
To drive your vehicle with the DRL off, turn the exterior
lamp control off. Then turn on the fog lamps or
parking lamps, and the DRL will turn off. The Headlamps
Suggested message will appear on the DIC display.
This will work regardless of gear position and whether or
not the parking brake is set.
As with any vehicle, you should turn on the regular
headlamp system when you need it.