Cadillac 2011 DTS Owner's Manual page 190

Clean the light sensor window, periodically, using glass
cleaner on a soft cloth. Gently wipe the sensor window.
Do not spray glass cleaner directly on the surface of the
sensor window.
This feature activates the headlamps and parking lamps
after the windshield wipers are turned on and have
completed eight wipe cycles within four minutes.
When the ignition is turned to LOCK/OFF, the
wiper-activated headlamps immediately turn off. The
wiper-activated headlamps also turn off if the windshield
wipers are turned off.
4-28
The light sensor is located
on the inside of the
vehicle in front of the
inside rearview mirror.
A warning chime will sound if the exterior lamp control
is left on in either the headlamp or parking lamp position
and the driver's door is opened with the ignition off.
Daytime Running Lamps (DRL) can make it easier for
others to see the front of your vehicle during the day.
Fully functional daytime running lamps are required on
all vehicles first sold in Canada.
The DRL system makes the turn signal lamps come on
when the following conditions are met:
It is still daylight and the ignition is on.
The exterior lamp control is in the off position.
The transmission is not in P (Park) (United
States only).
The light sensor is covered or not detecting light.
See Sensors under Dual Climate Control System
on page 4 34.
When DRL are on, no other exterior lamps such as the
parking lamps, taillamps, etc. will be on when the DRL
are being used. The instrument panel will not be lit up
either.
When automatic lighting is on and it is dark enough
outside, the turn signal lamps turn off and normal
low-beam headlamp operation occurs.