One problem related to headlight switch has been reported for the 2005 Cadillac DTS. The most recently reported issues are listed below.
The front head lights on my 2006 Cadillac Dts go out at all times. I have to continuously cut out and I have to turn the light switch off and on so I can drive at night. Ii previously owned another 2006 Cadillac Dts with the same problems. I took the vehicle to a Cadillac dealer kristal auto mall in brooklyn, NY and they fix the problem which they said was a faulty ballast. It was faulty on both headlights. And now in the Dts I have, it is faulty too. There has been a recall on this same issue in other gm vehicles.