The Foglight Issue

[41deacon]

My son just brought a 2015 Ford Fiesta SE. It had no fogs but it has existing wiring. I bought him some fogs and put them on ,I also changed the headlight switch to the one with the fogs on the switch. The question is how do I get the fogs to fuction? Do I have to to Ford to have it flashed or is there another way to enable them?

 

[scotman]

Unfortunately, you have to connect the vehicle to Forscan in order to add the fog lamp function into the BCM.
If equipment is added the canbus won’t recognize it until the “as built” menu is updated.

 

[Handy Andy]

IF you can note the color code to the switch, check for the Fog Light wire.





You can "bypass" that BCM issue if you locate the wire that GROUNDS the relay - you'll have to install the relay, and locate the wire that GROUNDS that relay that goes to the BCM.



See the Relay coil how it's wired?

That one that goes to the BCM - that wire is the one that goes to GROUND at the FOG light pin of that switch...

The BCM is it's pass thru, and that wire cannot be disconnected from the BCM directly - it will flag a note on the dash to let you know you have an electrical fault. Because of the FOG light wire to even exist - means the Fog lamp can be used, but will not be enabled unless you tap into the wire and bypass the BCM to the FOG light switch.

Remember this bypasses the AUTO and AUTO-OFF Battery Saver Modes so you will have to manually turn this light off when you're parked - that's on you.

Partly the reason for the BCM programming is due to the wide variety of functions and regulations - other parts of the world allow or require this vehicle to have - just in lighting alone. So if the "FOG" light won't work if everything is wired up - then you know what to do to make it a manual system like the older days.

I'm rebuilding a work in progress for the FOG light for I installed a separate system to use them as marker and turn - so as I rework the photos I lost in a HD crash - I'm currently working on a How to - to show "How I did this" it's a work in progress.

 

[41deacon]

Thanks.

 

[Handy Andy]

First, look at your siblings Fusebox,

Does it look like this?

This is the Fusebox from a 2018 Fiesta (New nose job thing)


This requires a considerable investment in time - so this is not an easy thing to just
drop them in. But this gives you the most reliable and serviceable way to install the Fog lights

The Older style - from 2013


Did you find the Relay outline?



The "Amazon Kit" looks like this...


Spade lug wiring


Notice there are small tabs that are pried outwards
- these sit in the socket and those tabs are bent out to rest in the notch on the socket in the Fuseblock.
So they don't fall out once the Relay is inserted.
One of the terminal Lugs, uses TWO wires (Black)
- so they can be considered the ones that route to POWER the fog lights - LOAD.
RED wire is heavy (Large #AWG) to handle the power FROM Battery to the Relay for LOAD (Black)

Most Relays come with a "schematic" identifying which pins do what inside that Relay's Housing

Ok?
So, Pin #30 would signal Power in Pin (common contact on switch - From Battery)
Pin #87 is the SWITCHED LOAD side of the Common #30 Pin (Output to LOAD)
Pin #85 is one side of the Relay Coil - Pin #86 is the other side of the coil

You don't have to tear apart the Fusebox,
You can use it's supplied "harness Relay Mounting" to install those wires
into their tangs - and wire the Fogs in manually.


You just follow the Pinout of the Relay, and map out which wires go to which contact.
I'm using the Wiring Harness supplied in the Kit as the guide.


Then the connector body - the one that mates with the Relay - you simply slide in the wires to their respective contacts. If you need help, just insert the Relay to fit the connector Align the tangs up, and drop the Relay in - that way you can see how the tangs line up and you just follow the Tangs using the Wires assigned to the Pin number.


Once aligned you insert the wire with the LUG and it's tab to the tiny rectangle hole side - and press wire into the connector - the small little bent out tab, will seat and snap (tink) setting the Lug to tang (Slot) into the connector - only one way, and holds the Lug in place, the keeper is the tab and the way it mates with the connector body. This holds the wires in the jack side of this, the "plug" is the relay.

IF you put the wrong wire to the wrong tang - just use a small eyeglass screwdriver or a paper clip and insert the flat (wire) on that area of the top part of the connector, press that flat blade into that small rectangle hole next to the slot, and pull the wire downwards, or opposite way - the tab will press in and release from the holder / keeper, letting the wire and it's connection LUG in the tang come out - then you gently re-bend the tab out and reseat the LUG into the tang in the correct hole​