2013/03/09 to consolidate all the stuff learned, and add some pictures.
So, here's a quick upgrade for some of you XLT owners (ymmv on an XL).
My 2006 F350 XLT was pretty plain, no autolamps, and no factory fog lights.
I miss the autolamps function from my Sporttrac... so I decided to do a little research and give it a shot and see what was involved in getting it working in this truck.
Turns out, all you (probably) need to do is order a new headlight switch from Tousley, Sunrisefordparts (or your favorite online Ford parts supplier). That's all I needed to do.
I also want to add some aftermarket fog's at some point, so I splurged and decided to order the headlight switch with autolamps and fog.
The part I ordered was 5C3Z11654FAA (w/autolamps and w/fog). $53 and change.
Popped the dash bezel out, popped the old switch out, plugged the new one in, and voila!
My truck has the manual HVAC controls, but it still has a light sensor on the dash (that little grey/black dome you see on the dash up at the windshield in the middle).
The sunload sensor looks like:
Because I have the manual HVAC controls, I only have two wires coming off mine:
The wires going to the sunload sensor (ambient light sensor) for autolamps are:
Light Blue (to VSM for autolamps)
or, if you have Electronic Ambient Temperature Control:
Light Blue (to VSM for autolamps)
Pink/Dark Green (ground)
Dark Blue/Orange (to EATC)
Obviously my XLT also has the right security module to go along with it, because the autolamps work!
The fog function works too... pulling out on the headlight switch does illuminate the fog indicator, the fog fuse is in the CJB, and that seems to mean that the internal fog relay in the CJB is probably there too.
In order to add fog lamps, you're at the very least going to need the factory fog pigtail harness (5C3Z15A211BA in case you were wondering).
This is what the pigtail harness looks like:
That harness plugs in to the existing truck harness (on my XLT). If you don't have the following connector in your truck... you're going to have to do surgery on the back of your CJB to wire out the hot lead from the fog lamp relay and run your own wires.
The mystery connector that the pigtail harness plugs in to is kinda hidden. It is NOT the one that you find under the driver's headlight... that is for the ambient temperature sensor. It is exactly the same connector, just the opposite gender... and not the right one.
The connector you are looking for is mounted with a push-in connector on the top of the frame rail, down under the air filter, see the following pictures for the location:
Remove the air filter to get to it easier.
The frame connector didn't have (on my truck at least) a plug in it... so there was some road grime and crap in it. I pulled it up off its mount, cleaned it out, and stuffed it back down where it came from. Then my pigtail harness plugged in fully and clicked.
Here is what the connector on the pigtail harness looks like that plugs IN to the one on the truck:
I chose the factory pigtail harness so I can splice it to my aftermarket fogs and not have to do any other wiring (uses all the factory wiring and fuses). FYI, the stub harness has H10/9145/9005/9006/HB3/HB4 female/plug connectors on it... so you might want to get the mating male/socket so you don't have to cut off the factory connector.
I found the following on Ebay that does the job nicely:
Here are some pictures of the above connector assembled and sealed to my light's harness:
I picked up a couple of 27W LED 60º Flood Beam lights off Ebay to try out... we'll see if I keep them. Pick whatever you want to use for your "fog lights".
One thing to remember if you end up troubleshooting... the fog circuit is only powered in START and RUN by Fuse 43 in the CJB. Yes, the light in the headlight switch will come on when you pull the switch out with the lights on even with the truck off... but there is no power to the fog lights unless the truck is running (and yes, I figured that out the hard way).
Just for completeness, these should be all the appropriate headlight switches and things, pick your favorites:
5C3Z11654AAA SW-6154 --- Headlight Switch, w/o fog, w/o autolamps
5C3Z11654BAA SW-6155 --- Headlight Switch, w/o fog, with autolamps
5C3Z11654CAA SW-6156 --- Headlight Switch, with fog, w/o autolamps
5C3Z11654FAA SW-6157 --- Headlight Switch, with fog, with autolamps
5C3Z15A211BA --- Fog light pigtail harness (fog lights back to frame connector)
6C3Z15200AA --- Lamp Assy Fog (Right)
6C3Z15200BA --- Lamp Assy Fog (Left)
W710891S437 --- M6-1x86.5mm Bolt (2 req'd per fog light)
W706599S439 --- M6-1x21mm Bolt and Washer Assy (1 req'd per fog light)
W520822S439 --- M6 Spring Nut (3 req'd per fog light)
Most of the stock bumpers should already have the spring nuts on the back side of the bumper, so you can bolt factory lights right in, if you like.
If you are going to add a future front receiver hitch at some point, be aware that you will probably have to remove the factory fog lights to do so.
The pigtail harness comes with little christmas tree push pins taped in to the harness... I think they fit in holes in the factory lights to secure the harness. Didn't have those on my truck, and didn't find any other holes to push them in to... so black zap straps it is to secure it all.
There's some other tidbits here and there if you scroll through the rest of the posts in this thread, but this is all the important stuff that should get you going.