Ford Focus RS Forum banner

Euro Rear Fog Light Installation

2 reading
81K views 140 replies 25 participants last post by  NBcfl  
#1 · (Edited)
We got a lot of snow this year and I got to drive a lot in limited visibility conditions. I decided I wanted to install the rear fog the European RS' have. I'll gather all the information I can in this thread (will update as I move along the steps) and use it to search for help with the wiring (hoping to figure out if it can be wired to the BCM and use the euro headlight switch with rear fog button).

Here we go! As I said I'll update this every step of the way. Posting this in the lighting section as I'm doing it for the purpose of adding the light, not for aesthetics of having the euro diffuser!

Step 1) Parts

Diffuser: P/N G1EY-17F954-A
--> Bought mine on eBay UK (used), also available from Ford Parts UK if you send them a part inquiry. I read on some other posts it was about 120GBP.
Rear Fog Light: P/N G1EY-15K272-A (also found it listed under P/N 2009072)
--> Found some listed on eBay UK, Ford Parts UK has it listed on their site for 185GBP which is really pricey!
--> Found some alternative, will confirm about fitment once received:
1) LuxVision (shipped next day from UK, in stock, similar design to the Ford unit): https://www.carbuildersolutions.com/uk/55mm-led-fog-light-with-clear-lens
2) Hella (6 weeks special order, looks identical to the Ford unit): https://www.rallylights.com/hella-55mm-led-turn-reverse-or-rear-fog-lamp.html
Headlight Switch: Found one used on eBay UK, simply look for one that looks as shown below (with rear fog button instead of hatch open button). Make sure it's not the one with the headlight beam adjustment button at the middle of it which is the most current one it seams.




Step 2) Headlight Switch Installation

I've done this already, once replaced the euro switch activates the rear fog indicator in the instrument cluster...hopefully this is good hope that the BCM actually has an output for the rear fog.

1) Pull back the door seal as required for dash side panel removal:


2) Remove the dash side panel, start from the bottom and slowly pry the 3 metal clips out as shown below:




3) Reach the back of the headlight switch and push it out...it comes out really easily, it's only held in place by the 4 small flexible metal tabs, disconnect wiring harness at back of switch (note the switch P/N seen below is the NA switch P/N, sorry I did not note the euro switch P/N, see step 1) for buying tips based on switch appearance):




4) See below the euro and NA headlight switch, install in reverse order (I know my dash trim around the switch is broken, found it broken after someone posted about this issue, will not bother about it):






5) Notice how the rear fog button now activates the rear fog indicator in the instrument cluster when pressed (requires the headlights to be on, might work with the corner lights only too I think):




Step 3) Diffuser Replacement and Fog Light Mount

Our NA rear bumpers do not have the mouting provision for the rear fog light (see pictures below of the UK bumper cover light mount). I will post information on how I mounted the light once completed. I did get a picture from another member who mounted the rear fog light using small brackets (see below). I'll either use this idea or fiberglass a mounting flange or depending on fitment mount it to the diffuser itself. Diffuser replacement should be pretty straight forward though (same mounting tabs/points).








Step 4) Wiring

To be updated once I figure it out (will need help)!

I hope there is a way to make use of the euro headlight switch to control the rear fog through the BCM. I found it has been done on Fusions so hopefully it can be done on our cars.

Otherwise I will wire it to a switch located somewhere within reach and view of the driver seat...plan B!

Step 5) Forscan

Might be required to activate the rear fog output from the BCM...
 
#2 ·
Basically what I need now is some help with the BCM / RS wiring.

Anybody here known for their knowledge of the RS wiring and BCM?

I'm hoping we can simply add a pin in en empty connector slot at the BCM and get the trigger for the rear fog working. Although it might not be as simple as this. I can execute the work no problem but need help figuring out where to pickup the signal from...if that is even possible.

Please let me know if you think of a member I should write to for some help to get started!

I wonder how different the BCM outputs are between the NA and Euro RS versions if anyone has the diagrams available maybe that could be a good starting point.

Thanks!
 
#9 ·
How would you actuate you trunk at this point? other than from the keyfob or the trunk handle?

Just curious. That's a lot of good info man!
Image
I only ever open it at the trunk. Never used the button on the headlight switch! Might bother those who actually use it though! Especially those who installed the stronger struts so their trunk actually opens when released!
 
#6 ·
As far as wiring I know from base model focus reading that the rear fog light wires direct to the BCM but there was really any proof to that. Supposedly there is connector in the trunk or rear tail light area. However for easy of the wiring, could you not tap in to the parking lights?
 
#8 ·
No, that is not a good idea. Not sure about the US, but I've heard in Euro if you run the rear fog lights during clear weather you can be fined. Even if there is not fine/ticket it is very rude to have that bright light on if not needed. Really should be wired with its own control (the headlight switch he already bought). Based on the fact that the LIN from the headlight switch goes to the BCM and the gauge cluster shows the rear fog indicator I'd guess the BCM is supporting it right now.
 
  • Like
Reactions: XRJoe
#7 · (Edited)
Looking at page 86-2 of the wiring diagram. Pin 10 of C2280B at the BCM goes to the rear fog light. I think the center rear goes through C431 Pin 9 to C699Pin1 fog light then back through C699 at pin 2 can through C431 at Pin 10 then to Ground G401. Wire between fog light and BCM should be RD-BK (CLS45) and from fog light to ground BK-WH (GD150).

Looking at page 151-17 C431 should be inside the rear bumper or behind the tire on the right side.

I hope this makes sense:
[BCM]>C2280B-10>----CLS45(RD-BK)---->C431-9>----CLS45(RD-BK)----<C699-1<[FOG LAMP, CENTER REAR]>C699-2>----GD150(BK-WH)----<C431-10<----GD150(BK-WH)----(S402)----G401
 
#10 ·
That it some very good info here! I actually was hoping you would post some info from other posts I saw where you had a lot of info on wiring!

Got a layout of the bcm connectors handy? I will start from the bcm and check if there actually is a wire in our NA connectors and trace if to the back of the car to see if it has voltage when the rear fog is activated.

That’s great information to get started that’s why I love this forum!
 
#14 ·
OP, you are definitely motivated to make this happen! I crawled around under the car looking for the rear fog connector but it wasn't there. If we have the wiring, it would likely go all the way to the rear fuse panel in the trunk. Maybe we are lucky enough to have the wiring go that far? I'm hoping that its coiled up neatly tucked behind the fuse box. I was going to poke around back there some more this weekend when I install my dsc controller.

Thanks for confirming that the euro switch activates the rear fogs, I'm guessing that there is some logic in to tell the bcm that it's not the trunk button.

The wiring diagram are like 15 bucks on eBay if you get stuck, or pm me and I can email you all the relevant pages.
 
#15 ·
Thanks for looking for the connector! I doubt there is anything behind our bumpers as you said! And the euro rs also have the backup sensors back there so I guess there’s a whole harness for their rear bumper that we dont have. If there is anything near the rear fuse box I’d be happy with that, in fact I’d be happy if there only is a pin at the BCM that provides current when I hit the switch! Running wires to the back is not a big deal to me!

I hope to have some time this weekend to look at the wiring based on the infos provided by @ControlNode.

I’m definitely planning to make it happen! Worst case if the BCM way is not possible I’ll run a dedicated switch.
 
#19 ·
#20 ·
Found another Focus forum (German I think) which had some good diagrams of the BCM and pins numbering that I'll use to get started.

Also found some good info on a fusion forum: How to: Mondeo style Rear Fog light

The fusion forum has the P/N's for the connectors that might be used to add a pin to the connector if the pin is not wired. It also mentions there are tiny numbers to help identify pin numbers so that should help too! Hopefully if our cars are not wired all that is needed is to add a pin to the harness and start from there to create our own wiring for the rear fog. In this case I'll have to determine if a relay is recommended VS wiring it straight to the BCM output. I know how relays work but I'm not an expert at knowing when they should absolutely be used...

Now I really hope to find some time to look for pin 10 at connector C2280B over the week-end!



 
#21 · (Edited)
My RS does have C431 on it, but only 2 wires, for the Intelligent Access antenna at the back of the car. Tag on the harness that goes onto the bumper is G1ET-15K868. But to get a really OE look you could by the pins and right gauge/color wires and run them though C431.

Or, maybe buy the Euro rear bumper harness and just remove the parts for the parking sensors, that would give you the plug for the rear fog too. Then you just need to go from BCM to C431 and C431 to ground.
 
#22 ·
@ControlNode thanks for another great bit of info!

Since I didnt buy the OE rear fog I’ll have to wire a connector anyways at the rear fog so I wont bother replacing the bumper harness but I’ll sure make my harness as stock looking as I can! Didnt really expect the wires to make it all the way to the bumper but at least now we know!!

I’ll try to confirm if there is an actuak wire in the harness connecting at the BCM over the week-end, and then figure out where it ends if it’s actually there!

Thanks again!
 
#23 · (Edited)
At this point I doubt you'll find a wire in pin 10 of C2280B, the wiring diagram show that as a direct connection to pin 9 of C431 and only pins 11 and 12 of C431 have a wire to them from the chassis side of the harness. My guess without looking at that BCM plug is that you'll likely be pulling the right interior apart if plan to route it with the chassis harness as it would go. I'm not sure the part numbers for the pins, but I can say the book shows 20 gauge wire. But if you get the right pins (1 for C2280 and 2 pairs of male/female for C431) to insert into the plugs it should not be hard: One power wire from BCM to LED through C431 and a ground wire from LED to ground point (looks to be near right tail light) again through C431.

But, if there happens to be a wire from pin 10 of C2280B, look around near the rear junction box for a 2 pin plug not connected to anything (C436), that may be there to support a left taillight fog light and is from the same pin on the BCM. If that exist may just need to run a wire from C436-p2 in the left rear area of the car to C431-p9 on the right rear area of the car.
 
#24 · (Edited)
Yup no wire at pin 10 (see attached picture with red retainer taken off to look at the pins). 1 is at the top right!

Luckily I went to my local scrapyard this morning and pulled a spare connector of a 2013 focus.

I pulled it apart and now have 27 wire pulled out of it with the pins! Plus now I know how to proceed with adding a pin without breaking anything on my car! Will choose one of the bigger gauge wires and insert at pin 10 see if I can get a signal for the rear fog! Might need to pull the glovebox out cause there is little to no slack on that top connector (also practiced that on the scrapped car)!!

Will post details on how to pull connector apart and add pin when I am on my computer. It’s pretty easy actually!

If it works I’ll also have lots of spares wires with pins I can give away for free!
 

Attachments

#25 ·
Added a wire at pin 10. Thought it worked for a second BUT that’s just because I first tested it with the fog turned on..was excited to see the voltage show on my multimeter until I turned it off and still had voltage.

So it’s putting out 10.XX volts all the time no matter what I switch On/Off.

Could there be some Forscan programming required, like the Fusion/Mondeo guys did?

I guess next thing is retrieving the asbuilt data from a euro RS and comparing with mine, starting with comparing the lines found on other platforms!

Unless more wiring or wiring to a different pin is required on our NA RS. @ControlNode if your wiring manual is showing those wires could it be applicable to the Euro RS only and ours would be different in some ways like the rear fog output from the BCM? I’m done for today but will look further into it later this week. Thanks again for your help identifying the fog wires!
 

Attachments

#26 ·
The book appears to have multiple markets info in it, I know it is for my car though as it has Sync3 info, NA was only market with that in 2016. But in the same logic it list non-Sync3 info, and we know all of NA RS came with Sync3 only.

This info is more of test at owe risk: The wiring for the rear fog does not show these pins as related, but looking at the C2280B connector view there are several pins in addition to 10(RD-BK) that show that same Circuit ID (CLS45) and list (FOG LIGHT REAR +) as the function. Pins 9(WH-GN), 12(VT-GN) and 13(VT-GN).
 
#32 ·
More Info on those pins from section 90 and shows the connector view info to be misleading:
C2280B
9 - Stop Right Rear
12 - Stop Left Rear
13 - Park Right Rear

The the diagrams in 90 can't even agree on how the rear lights are wired, on page 90-3 it has them as pins 19 and 20 of C2280B, but the connector view has those as open, but on page 93-1 it has reverse going through C2280E (pins 19 and 20), the connector view for C2280E shows these are for Rear Fog lights.

Basically Ford has released the most **** Electrical Diagram I've every really looked at.
 
#27 · (Edited)
I’ll check pins 9, 12 and 13 next time I feel like bending under the dash panel! Thanks again for the wiring tips!

Probably wont be this week as I’m going ice racing on friday so I need to prepare for that! Last chance for making it work without looking into Forscan I guess.

I feel I’ll be sore tomorrow from all the contorsion!

Edit: the colors of the wires at pins 9, 12 & 13 on the car’s connector match the wiring manual colors, that’s good to know too!
 
#36 ·
Thanks for your PM, just replied a few minutes ago!

Thanks for your help I wont be working on the car itself for a few days life and work are keeping me busy these days, but I’ll sure plan the next trials as much as possible reading through what you guys provided in tha last few days!
 
#37 ·
Oh and I received my diffuser yesterday but all but maybe one mounting tabs are broken which was not mentionned in the add and obviously when I asked about any damage they did not mention this either! Will be looking at my local plastic welding shop to fix those before installation. I got it for cheap so it’s still worth it if they can fix it, the whole tabs are there but broken at one or the other edge from being pried off the bumper cover I guess.

Otherwise it looks pretty good it only has one small scratch which will be barely noticeable once installed.
 
#41 · (Edited)
Got my luxvision rear fog light in the mail today. Surprised to find out it’s only using that one LED but it’s real bright anyways! Those other reflectors that are not used for the rear fog must be used on the turn signal or brake lights version of the same housing.

I’ll compare with the hella version when it comes in (still 3-5 weeks from now though). I’ll try to make my foglight mounting setup easily swappable so I can swap the hella in there when I get it (if I actually reached a point where the diffuser is mounted by then).

Good news is the 55mm housing is a perfect fit in the euro diffuser opening, so no need for the overpriced OEM rear fog light.

Cleaned up the diffuser too. It’s got some small scratches but most will be barely noticeable once installed. Might take Friday off and bring it to my local plastic welding shop to see if they can fix the little tabs, most of which are currently broken.

Then I’ll find a way to mount the light, planning on mounting it directly to the diffuser to make it easier to center the light in the opening. It doesnt weight much anyways.

I’ll probably have some time to go back and look at the bcm again over the week-end to look at the other pins which might be providing power for the rear fog.
 

Attachments

#42 ·
I was just thinking to ask about progress on finding a signal to control the light.
 
#43 · (Edited)
Last 2 weeks were busy with work, funerals (on the inlaws side) and GF's sprained ankle...was on a 6 hours trip (both ways) for the last two week-ends for that! At least some parts showed up in the meantime to show some progress!

Hoping to dedicate some time this week-end to the wiring from the bcm again!
 
#44 · (Edited)
Made some progress this week-end on fixing the broken tabs on the diffuser and mounting the light straight to the diffuser.

Picked up a 2 wire sealed connector from some Chrysler at the local scrapyard and fitted it using waterproof crimp unions and heatskrink tubes, trying to make it as stock looking on the wiring aspect too.

Made some .016” thick aluminum doublers for all the broken tabs, bonded them in place using epoxy adhesive and clamps. I hope it will still fit fine when inserted in the bumper cover but it’s pretty thin so it should be fine.

To mount the light I used a 2in abs plumbing pipe union (less than 1$) and a stainless wormgear clamp (cheap although I dont remember how much). Cut three little slits on one end to fit inside the diffuser and 3 larger slots at the other end to rest the light at the proper depth. The 3 small slits allow it to sit at the bottom of the light opening without getting rid of the 3 little tabs, which actually make contact with the light and help centering it in the opening. Light is held in place with a wormgear clamp which fits just right behind the light mounting tabs. Bonded the mount to the diffuser using epoxy adhesive. It’s just solid now! Will update the first post with more details and pictures when I’m back on a computer. This will make it much easier not having to mount the light to the cover and then adjusting it in a trial/error game putting the diffuser over it! The light is not heavy at all so it will be fine being held by the diffuser only.

Edit: the luxvision light as a small corner radius on the lense which makes it hard to decide at which depth I want to mount it. Looking back at the pictures I posted it may be protruding too much now when compared to the stock light on the euro RS. I'm curious to compare the lense edge shape to the Hella light when I get it. For now I might just shim the luxvision light further back into the diffuser a bit, but it's easily adjustable now just need to shim the 3 little light mounting tabs.
 

Attachments

#45 ·
Found a listing for a supposedly OEM light on eBay uk:

https://www.ebay.co.uk/itm/GENUINE-...EY-15K272-AB-2016-2017-2019/362588742985?hash=item546bf92549:g:GHYAAOSwUvFcj2VB

Interesting how the lense has the Hella brand on it and how the wires seem to not have been cut but rather pulled/forced out of crimped connections.

If it is indeed OEM it confirms the Hella rear fog light I found on rallylights.com is the exact same one as the OEM light (without the connector) for only 40$us which is a sweet deal compared to buying the OEM from UK! I'll most likely use the Hella one when it comes in as I prefer the way the lense looks VS the more aftermarket looking luxvision light. Unless it is not as bright then I'll probably use the brightest out of them.
 
#46 · (Edited)
Installed the diffuser this afternoon, along with adding a hole for the rear tow hook. The little repair doublers at the mounting tabs fitted just fine. And the rear bumper heat shield fits back over the light too. Routed the wires for the light through the passenger side taillight feedthru.

The light is powered by 2 6V batteries on the attached picture (was making sure my connections were working before securing the harness and putting the bumper harware back in.

Will also post more details about those steps when I am on my computer. Planning to go back to the bcm tomorrow to check the other pins as suggested earlier. Would be nice to find the power source tomorrow and be done with this mod already!

Edit: ran all around town to fit a suitable plug for the rear tow hook hole! Ran out of time to dig in the bcm...might have to wait to later this week or next week-end. It’s next on the list though so I can’t procrastinate this anymore!
 

Attachments

#47 ·
Something that may interest you, I took a dive into FORScan to change my TPMS threshold and extend the play time on the radio. I also looked for any rear fog setting, the only one I found was for locking out the rear fog if you're towing. Honestly, if your BCM turned on the light in the dash then it should be putting out power from the BCM to rear fog wiring somewhere.
 
#49 ·
Thanks for looking at it in Forscan, I’m hoping it will be as easy as findinh the right pin at the bcm, I guess we’ll see soon as this is all that’s left to finish this project!

I just kept this last because my garage is small and I cant really open the passenger door completely to work under the glove box so it’s pretty tight working in there and not so much fun!