I've a 2004 DTS that using driver 1 key doesn't care if the sun is out bright at high noon the Headlights Suggested warning comes on. With key 2 everything works normal -- bright sun no warning. Dark? it suggests that headlights are needed. I can fake it by turning on the twilight switch but that just turns on everything in the middle of the day. How can I retrain it?

are your windshield wipers on?

The wipers are off. I just bought this 04 and I don't know if it has the automatic wipers or not. You may be on to something.

I worked with it a little more yesterday and figured out that I was wrong about key # 2 being ok. Both key fobs do the same thing. High noon, clear sky start motor and get headlight recommended message. Turn message off. Message comes back on, Turn message off again and it stays off.

The sensor in the middle of the dash may be bad. The little black buldge in the center of the dash, by the speaker.

Thanks all. As it turns out /cadillacsts2003 you were right on. The wipers were one click on delay (haven't seen wiper blades move yet). Once I turned the wipers to off everything works perfectly. My 99 had the habbit of the trunk lid popping open when I started the motor. As it turned out my battery was going bad and this was the way that the 99 decided to warn me. I figured that the 04 might have had something similar. Thanks again.