OK. Here we go.
Have you checked out this sticky?:
How to: Auxilary/offroad lites
I highly recommend using a relay! I have my lights wired so that they can only come on with the parking lights and I have a switch also so I can shut them off when the parking lights are on. I picked up the relay
(Click Here!) and the switch
(Click Here!) at Radio Shack. I got the wire at Walmart. I used 14 Gauge Red
(Click Here!) & 14 Gauge Black
(Click Here!).
This is the diagram I used for wiring my lights. The relay is triggered by the parking lights, turning on my aux lights, and the switch allows me to turn off the lights:
I found a great path for running wires through the firewall on my '02 XLT:
This is the view from the engine compartment. The access is behind the brake booster. Look behind the brake booster and down and you will see it.
This is the view from inside the Ex. Follow the brake pedal up to the firewall and look to the left. The red arrow points to the piece that you peel back and the black arrow points to the grommet:
This is where I installed the switch. With the switch in the on position, the fogs only come on when the parking lights are on. With the switch in the off position, the fogs never come on even if the parking lights are on:
I tapped the parking lights at the driver's side parking light itself, not a big deal since you have to route wires in that area anyway. The picture is from my how to for installing signal mirrors, the link is in my signature. There is some good info there for routing the wires.
Peel back and remove a portion of the plastic wrap - The red arrow indicates the quick splice connector connected to the Green w/White Stripe wire for the signal mirror - The white arrow indicates the quick splice connector connected to the Brown wire for my fog light relay.
Here is the pic of the grounding points. The red arrow indicates the grounding point for the lights, the white arrow indicates the grounding point for the relay & the switch, the yellow arrow indicates where I mounted the relay, the blue arrow points to the wire run from terminal 30 on the relay to the positive terminal on the battery (including in-line fuse):
My relay wiring is as follows:
Term #30 - wire run through in-line fuse to positive terminal on battery
Term #85 - wire run to ground point indicated by white arrow
Term #87 - wire run and connected to positive wires on fog lights
Term #86 - wire run to load side of switch located inside vehicle.
The switch shown in the link has 3 terminals (ground is required to illuminate the LED indicator light):
Line - wire run to parking light circuit at driver's parking light
Load - wire from term #86 on relay
Ground - wire run to point indicated by white arrow
If you use a switch without an indicator light then the ground wire is not required.
When wired as above, the aux lights can only come on when the parking lights & the switch are on. When the parking lights are on you can shut off the aux lights with the switch.
I hope I didn't confuse you too much. Feel free to ask any questions.
