On my 2000, I have the "auto" type light switch, with the timer off to the left for keeping the lights on after shutting off the engine. But if I use it, the lights are just always on when I start the car, even in the blazing sun. So, I don't know whether I simply don't have dusk-sensing headlights, or whether I have them and they don't work. Is there any way to tell?

All vehicles we've owned over the years that have a position for the headlight switch called "Auto" has always meant that the vehicle indeed has dusk-sensing headlights....

The sensor is in the center of the dash, you don't have anything obstructing or covering it by any chance?

There are two sensors, with nothing obstructing either. A bubble shaped sensor definitely has something to do with the alarm, as it has a red light to indicate it is engaged. And there is a flat square sensor. My understanding is that this array includes a solar sensor for the A/C, which I think may be the flat square one. Does the dusk sensor share the same bubble as the alarm sensor/light?

Reviving my own thread here... I was wrong about the shape of the dashboard sensors -- they are both domed. The one closest to the windshield is oval and houses the red light for the alarm indicator in one half. The other is circular and closer to the interior of the car. Does anyone know which one houses the dusk sensor for the headlights?

the one in the center of dash next to windshield, fell off and got sucked up by the detailers vacuum...any ideas exactly what this part is called and where i could get one?

Start with a jag dealer to get a feel for the price - though I'd hope the detailer is paying!!

Any wrecker should have them as they appear to last the life of the car - except yours LOL