I have a 1997 Seville STS which has been a great car and nearly trouble free for years. Until now... While driving at night, the headlights and dashlights will occasionally (and quite unexpectedly) go out. Manually pulling out the headlight control knob will bring the headlights back on but the dash remains dark. Pulling off the road and turning the key off/on will often restore everything back to normal operation. But obviously this is a rather "exciting" and dangerous condition. The twilight sentinel switch is my primary suspect. However, I would appreciate hearing from anyone who has resolved a similar problem or has a suggestion. Thanks in advance!

I found the answer! Turns out the photo sensor in the grill (or so I was told) had failed. Replacing the sensor has solved the problem. I hope this helps someone else.

Thanks for the info . I purchased a babied 96 sls a couple of months ago and just the other day the same thing happened to me . I was about to pull over , then bang everything came back on . Now I know where to start .