Mk3.5: How To Fit ST/RS Headlights On An SE

If we’re being honest, lighting has always been a weak point of the Mk3 platform. We’re excluding ST/RS/Electric models in that of course, although even their factory lighting in North America lacked a feature or two as compared to overseas models.

When the Mk3 launched in our markets one steady complaint from reviewers was that the standard halogen lighting just wasn’t up to par with what the competition had to offer, and by the time the generation ended in 2018 it hadn’t really been improved. To be fair Ford did make a minor update as part of the 2015 facelift by offering LED “eyebrows” on certain trims and packages, but even those weren’t standard; however, the S through Titanium models still relied on halogens while the STs, RSs, and Electrics (which I swear only three people ever bought) had projectors with HIDs*.

*Standard on Canadian STs and Canadian/US RSs, optional on US STs

There are a few solutions to this: one could turn to the aftermarket and pick up one of the few styles of lights offered, the factory lights could be pulled open and retrofitted, or some hand-me-downs from one of the higher trims could be swapped in place for an OEM+ approach. Thanks to Kyle fitting some aftermarket units to his 3.5 ST earlier this year, I had the opportunity to take the OEM+ route and have some vastly-improved lighting on the front of Arabis; especially useful during our winters, given the very short days.

Before we go any further though there is one very important note to make here, and it greatly influenced my decision to grab Kyle’s lights: fitting factory ST/RS headlights is merely a matter of plugging them in, bolting them in, and coding – on the Mk3.5s only. Prefacelift cars – 2012 through 2014 Mk3s – also require some wiring hacks in order for the factory ST lights to function. With the process being so straight forward on the Mk3.5s it was a no-brainer for me to grab these lights as we could quickly and easily have them up and running on the car without having to mess with any wiring. I have some quick notes regarding the swap on prefacelift cars later on in this post, but the video (linked later on) and this article are centered around Mk3.5s (2015 – 2018 cars) specifically since that is what Arabis is.

*I know the whole Mk3/3.5 terminology can get a bit confusing at times especially given Mk3 can be used to refer to any 12-18 car but 3.5 only means 15-18. Today’s guide is for 3.5s. 

The install of the lights themselves is super easy, and as noted in the video the most challenging part is just undoing the connector to remove the originals. That’s not a joke; that little pest always seems to put up a fight, being reluctant to let go of whatever headlight it’s connected to. Anyway, a pair of torx screws holds each light in place so – depending on how cooperative the connector is – the lights can be changed out in seconds. Once plugged in and bolted in though, they won’t be ready to go without some coding (which was already complete when the above photos were taken).

There are a couple of programs you can use for the coding – FoCCCus or FORScan. We used the latter (FORScan), and a big thank-you goes to Brian for this as he is the one in the group with the OBD2 adapter and software; he came over a few times so that we could run through the car’s settings to test everything out and also explore some other minor “modifications” – more on that in a bit.

In doing research for this swap and article, I did discover a couple of owners noting a setting which we didn’t even have in FORScan’s menu, seeming to be the equivalent in FoCCCus if I’m not mistaken. I will note both in the following guide, so don’t worry.

The settings required to enable the ST/RS headlights are the three you see highlighted here. Given this is Canada and we have DRLs on our vehicles, we found we had to tweak the “Daylight running lamps” setting in the middle but as far as we are aware American vehicles will only need the other two adjusted.

FORScan settings for OEM ST/RS headlights: 

-Headlights, type: GDL advanced front lighting system with static bending, light and auto dynamic adjust (*This may be listed as Alternate HID or Alternative HID in FoCCCus – I found conflicting reports from other owners)

-Dimmed dipped headlights: Without dimmed dipped headlights

-Daylight running lamps (Canadian vehicles): Dedicated Day Running Light in Pos ‘0’ and ‘POS’

While we have not had an opportunity to plug an actual Canadian-market Mk3.5 ST or RS in to FORScan yet, comparing functions with friends via text confirmed that these settings had Arabis’ headlights operating as they would from factory. The LED eyebrows are on their full bright setting in OFF and PARK, with the HID lows activating (and LED brows dimming) in ON. High/low switchover works perfectly as well, and the amber marker lights activate properly in PARK and ON also. The only exception to all this is a lack of a cornering function as non-ST/RS models do not have the cornering module and with a different harness, it can’t be plugged in. The results of this – as shown in the video – are a quick error message on startup (which you can hit OK to clear off the screen) and a permanently-lit yellow “i” in the bottom of the cluster (between the fuel and temp gauges). If you ask me, these are small prices to pay for the much better output of the factory HIDs, and perhaps at some point a fairly easy workaround will be discovered to avoid the fault. Also worth noting in case any overseas readers are wondering, Canadian/US cars never had auto leveling so we can’t offer any insight into enabling that feature.

And in case you wanted the tutorial in moving picture form, here’s the video as promised!

Extra coding: 

At this point you could disconnect your car and call it a day, but curiosity may get the better of you when presented with the huge list of settings that can be changed. Brian and I took the opportunity to change three more settings on the car – for safety or security – and in case anyone reading this is interested in doing the same we made sure to grab photos for them as well.

Fog lights with high beams

As programmed from the factory, Mk3/3.5 Foci cannot run their fog lights and high beams at the same time. If your fog lights are on and you activate high beams, they will instantly switch off only to turn back on once the car returns to low beams. Changing the “foglight function” setting enables them to be run simultaneously.

-Foglight Function: Foglamp without restrictions

Emergency brake lamp

I’m not sure how many (if any) Canadian-market vehicles come with this feature activated now but Foci have the coding for it, just waiting to be turned on. Under extreme braking the car will now automatically flash the hazard lights to (hopefully) further draw attention of other motorists. There is also the option to have the car flash the brake lights instead, but having the hazards flash simply adds to the light on the back of the vehicle and amber lights do a much better job of getting attention than red anyway.

-Emergency brake lamp: With Emergency Brake Light – Hazard Warn

Auto Relocking

This last change wasn’t shown on video as it was carried out just after, but it’s one I’m quite pleased with just for peace of mind. With this enabled, if the car is unlocked and then receives no other inputs (doors opened, buttons pressed, etc.) it will automatically relock after 45 seconds. Not that the buttons on a Mk3 key are that sensitive anyway, but it’s nice to know that if one should accidentally be pressed the car will lock itself back up shortly after.

-Auto Relocking: Auto Re-locking (could they not decide if they wanted to hyphenate it or not?)

A few extra notes on ST/RS HID swaps:

Before wrapping up the post tonight there are a few final notes I wanted to make to go along with the tutorial, and also touch on the prefacelift swap.

First up, availability. Here in Canada all STs and RSs were effectively fully loaded, so all had the HID headlights. For our American readers you’ll be limited to pulling lights from Mk3.5 ST2 and ST3 models, though all RSs still received them too. You could of course buy lights brand new but you’re looking at a couple of thousand each at a minimum so I doubt anyone will.

For features, as noted earlier in the post, the cornering function will not work as the lower-model cars do not have a cornering module or even a place to plug one in. You will have the warning message on startup and illuminated “i”, at least until someone figures out a workaround. Headlights from overseas markets may also be capable of self-leveling but that feature was never available here so good luck in getting it to function. Haha

And finally, the prefacelift Mk3s: As with facelifts, all Canadian STs received HIDs from factory though they were only on ST3s in the USA so may be a bit trickier to find down there. I came up with slightly contradictory findings on FORScan coding (some noted that only “Headlights, type” had to be changed while others stated you also had to change “Dimmed dipped headlights” as you would on a 3.5), but the fact remains that coding alone doesn’t enable them to work. Three wires in each headlight have to be grounded but at this time I do not have a confirmed wiring diagram to provide for this. Reportedly they are plug and play (without wiring tweaks) on ST2s and possibly ST1s though, which is interesting. You may be crying out “doesn’t Brian’s Titanium have ST HIDs?” and yes it does, but that car has seen heavy rewiring for custom work throughout so isn’t really applicable as reference here.

And with all that, I think this little guide can be brought to a close! In the month or so I’ve been running these lights I have been extremely pleased with the improvement in visibility and the car looks a little bit better with not just the black housings but the LED strips too; Arabis specifically had the super-base headlights that didn’t even have the LED eyebrow before. It was luck that Kyle happened to be changing out his lights and I was able to pick these up, but regardless of how it came to be I think we can call these the best upgrade the car has seen yet for their appearance and performance.


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