it's more of a power/load problem. these days manufacturers are cutting down the wiring to the bare minimums to save costs (maybe weight, but I doubt it.) my dodge shadow has 14 and 16 gauge wiring in places that my neon and jeep are using 18 gauge. when you start doing that there's no safety margin for the extra power needed to run a trailer light setup. chrysler's not alone in doing this either. most manufacturers have cut wiring down dramatically.
We had an '08 Ford Escape that didn't come with a hitch or wiring. No big deal finding a hitch/harness as there are millions of Escapes on the road, right? WRONG!
The hitch was no problem but the wiring harness was a royal PITA! Ford changed the wiring mid-year so the harness I purchased didn't work properly. Trailer lights worked intermittently, funky things happened to electronics (stereo, interior lights, etc.)
After lots of time on the phone with Curt Manufacturing Tech Support they finally MADE me a harness with a 12-volt line to run directly to the battery, and...
Viola! Problem solved.

p:
Jeepman56, with the price you got on that hitch/harness package you're still WAY ahead cost wise even if you purchase the Hopkins harness. Put the other harness on e-Bay and get a few bucks back. You'll be ahead of the game by avoiding headaches down the road.
With as delicate as the Libby can be with its battery using the Hopkins harness is 'headache insurance...' :favorites68:
My 2 cents...
Bob