I have some wiring behind my front bumper which would appear to be for factory foglamps. However, when I plugged a set in, they didn't work. Where do I locate the relay? I believe the lampswere optional on this model....

 

if u have a 01 and up u are missing some parts and software humm never tired it so cant tell u if adding the other stuff will even work. Yes it has the wires and thats because it is less expensive for chrysler to make several harnesses instead of just one for all vans.
U are missing the switch in the dash, The front controler and the relay.