Well some of you may of seen that I've been trying to add factory fogs to my 04 Ranger 4x4 which had the foglight delete plates. My truck had no fog light wiring under the hood and I assumed there was none under the dash. So I hooked up the under hood part to the factory distribution block and into the factory relay location. When I got to the underdash part I noticed I had the factory plug in underdash but no wiring under the hood. I traced them all out and this is what I found.
Black wire = ground and was hooked up and needed nothing
Red/Blue = illumination and was hooked up and needed no work

Blue/Black = ground on relay
Tan/Orange = input from relay for illumination
Now these two wires went down to the big plug under the dash just above the parking brake. The wires came to the plug with the male pins but the female side of the plug didn't have the wires installed. You can go out to the salvage yard and get some of these pins and install them. They're are 3 sizes of pins in this plug big, medium, and little. These wires require you to get medium sized female pins. They actually were the same size pins as the female plug for the fog light switch, so I removed the Tan/Orange and blue/black wire I had from a junkyard fog light plug and plugged them into the big plug above the parking brake. This is where I spliced in my wires from the relay. This allows you to reuse your factory underdash wiring for your fogs. I've read of people here totally adding there own underdash fog wiring cause they're factory wiring wasn't hooked up. This will take care of it.

 

It is just me but if you are adding lights that were not already on the truck as OEM you should stay away the harnesses as much as possible.

Again, if I were doing it (IMHO):
Mount the lights where you want them and mount the relay close to the battery area.
Tap the low beam light wire for a control wire to actuate the relay (pin 86).
Ground the relay from pin 85
Run a new fused wire from the battery to pin 30 on the relay
From pin 87 on the relay run a wire to the lights.

The only problem will be finding the low bean light wire in the harness.
Size the power wire according to amperage draw of the lights, 10 amp = 16 ga, 20 amp = 12 ga, 20+ amp = 10-ga (or do like me run 10 ga for all power to lights).
The wire used to tap the low beam wire can be 18-ga BUT with a 3 amp in-line fuse close to the wire tap.

I guess the biggest problem will be deciding where to mount the lights.

Now if you want a dash switch to go between auto or manual, that will take a couple extra wires.

NOTE: Grounds are important make sure they are connected well to bare metal.
If you want you could run a ground wire to the lights also eliminating the lights grounding through the frame.

later,