I've been studying the 2003 Wrangler wiring diagram for days now since I'm looking to use as much of the stock wiring as possible to add fogs to my 2003 X which is only partially pre-wired for fogs. I'm probably going to be adding some Hella 500ff's on Wed. or Fri. this week.
Originally Posted by jkp
That plug is for the Temperature sensor that would be on the rear view mirror.
The factory fog light plugs are under the fender well in the same harness that feeds the turn signal and parking lights.
This thread which is for a 2006 X is a good starting point for reference the wire colors for an '03 are different http://www.wranglerforum.com/f5/afte...ng-121355.html
If you don't have a fog light switch on the multifuntion switch (the one you turn the headlights on with etc.) you'll need to do some additional wiring.
You'll either want to get the multifuntion switch C1 with the fog light switch from a sport or splice some wires from Pin 13 (PK/LG) and Pin 14 (WT/OR) to wire in a switch.
You'll be missing the wire that is LB (light Blue) in Conenctor C110 pin13, that is the feed to the fog lamps. You'll need to splice into the feed from the relay in the PDC to finish the circuit. A good splicing point that I'm pretty sure is the best place to do it is at Pin 21, Connector C170 under the drivers side dash near the kick panel.
I haven't had the change to confirm all the wiring from the manual but I'm pretty certain this is all correct.