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Old 06-30-2012, 12:01 PM   #18
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What I Drive: 2012 Ford Focus S Ingot Silver

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Update - I finally have working fog lights the way i want them to work.

And other than the harness up front for the fog lights themselves. you need about 2 to 3 feet of wire (up to 6 wires)

Lessons Learned So Far:

Ford runs EVERYTHING through that damn Body Control Module. And the S model DOES have its own version of it. Replacing it with the proper Module for fog light equipped cars is way expensive, requires dealership installation (the new module needs to be programmed and may not be possible because this stuff is all VIN based and is done "as-built") and is more of a pain in the butt than i cared to deal with. SO....

I have 2 choices..
1. Have decorative non-functioning lights...
2. Create my own fog light control module...

Heres what you'll need...
(Sorry No pictures.. Mom wanted her camera back, but i will provide illustrations where possible...)...

From Radio Shack...
1 5" x 2.5" x 2" Plastic Project Enclosure Box.

From Any Parts Store...

2 Bosch Style 40 AMP SPST Relays... (advance auto parts has these)
6 1/4 inch male Blade Terminals for 14-16 Gauge Wire
9 1/4 Female (Fully Insulated) Terminals for 14-16 Gauge Wire
1 of each T-Tap Inline Splice for (10-12Ga, 14-16 Ga and 18-22Ga)
1 In-Line Fuse Holder (ATM style) with 12 Gauge Leads
1 15 AMP ATM style fuse
1 Ring Terminal for M8 (I believe) size bolt/Stud
2 flat washers for M8 Bolt/Stud
1 Illunimated (color don't matter) Rocker switch
14 Gauge Wire
18 Gauge Wire
4 inch Tie Wraps
8 inch Tie Wraps
Black Epoxy (You'll Need Quite A bit)
a few of those premixer nozzle things for the epoxy that let you just squeeze the stuff out of the syringe directly..

Tools You'll need..

T25 Torx Driver
Exacto Knife (or, a very large safety pin or medium sized paper clip)
Wire Strippers/Cutters/Crimpers
Needle Nose Pliers
Side Cutters
10mm Socket and Ratchet.
tiny Flat Blade screwdriver (the itty bitty one with the 1/8th inch tip)
Black Tape
Soldering Iron and Solder.

What we are going to do is build a Fog Light Control Module Relay Box that will run the fog lights only when certain conditions are present. (Ie only when we want them to be on)...

Since our cars like to kick the parking lights on when we use the key fob to unlock the car, we can't just simply tap into the parking light wiring just by itself.. otherwise the foglights will light up when ever the parking lights do, Since i live in an apartment this would really piss off my neighbors. Plus it don't look very professional..

But also we just cant tap in to the ignition either or our fogs would be on when ever the key is on... (Don't want that either)...

By using two relays and feeding one relay off the ignition feed, and one of the parking lights feed, and having the fog lights driven directly off the battery, We have more control over when the fogs can come on. I wired mine so that both relays have to be active in order to have the fog lights active. The ignition relay is first in the line, followed by the parking lights relay. if either the ignition switch is off, or the parking lights/Headlights are off, the fog lights will be off too.

Second reason for the relay setup, is since every light in the car is driven off the BCM, there is a possibility that by driving the fog lights directly off the parking light circuit (without their own power source), it could overload the parking light circuit inside the BCM and possibly burn the traces for that circuit on the circuit board (which means you have to replace the BCM). Granted nothing may happen but since they want more than the GDP of some small African Nations to replace the damn thing, Driving them directly off the parking lights or any other BCM output is something i don't wanna try.

Overall, building the Control Module and tapping it in to the car's wiring is not really very difficult, but if you don't like dealing with wiring or unsure, i wouldn't try it. Since we are dealing with the body control module, it can be damaged if you aint careful.

All I Can say is this did work on my car with no ill side effects during testing. If you screw up your car, I'm not responsible..

I still need to epoxy seal my box, and do the final mounting where its going to live and put the thing the rest of the way back together. I need to also make the diagrams for the building and installation and once i get that done, I will post the instructions for building the control module and the installation in to the car...

So.. stay tuned...
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