The previous couple of vehicles I have owned, had an automatic option for the headlights to come on once it was dark enough outside. I know some people don't like this feature, and my 2001 Grand Cherokee Limited has the ability to cancel this, so what I am looking to do is add this capability to the 8.
Any suggestions on possible ways of doing this?

My first thoughts are using a photocell wired into a low power relay to be the trigger for the headlights to come on. I'll use one of the available switchblanks (next to the DSC switch) to enable/disable the auto-on mode. I might also include a pot to give some adjustability to when the lights come on.

I haven't really had the time to research any further and I am not an EE just some controls experience in the past as an ME. I am certain there are a few more details to work out, I just wanted to throw the idea out there and see what anyone thought about it.

That sounds like about the easiest way to do it. Just wire it into a switched source and use a relay. You don't want the lights automatically coming on when the car is off. I would wire this in with the headlight switch in the on position. That way you just leave the switch on and forget about it. If you just decide you don't want the lights on anymore you can just turn the switch off.

that is a great idea, I am so used to auto headlights.
I am no expert but my humble thoughts:

1.It would have to be a double pole relay to switch on the lights and the headlights.

2.The switch could be a double pole/double throw switch, on one side let the power go through (stock config) and on the other through the photocell/relay combo. The photocell/relay power will have to be operational only when IGN is on, maybe through another simple relay.

this sounds exciting

3.switched power could come through the main light switch on the steering stalk

These are great suggestions, where would you mount the photocell? The unit I first looked at was 2.5 cm x 4 cm. it is low output at .45V max so I am going to have a difficult time finding the appropriate relay - or - I'll have to brush off the cobwebs in my mind and try to remember how to boost that to a usable signal. Higher voltage photocells are available, but they become large quickly and would be aesthetically displeasing (i.e. ugly) and I don't want that in my car. This is where I can use some suggestions especially from the electrically gifted members of the forum.

I know it's more fun to roll your own but a quick search produced this:

http://www.autobarn.net/des20012.html

Great find, the only thing I don't see is adjustability on the light sensitivity. I checked JCWhitney and couldn't find this. Thanks for the post. Anyone have one of these?

great find. Looks like a solution to all our problems.

I wonder if there is a way to override it and have the lights on during the day, e.g.rain.