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Euro trailer plug/harnesses

12K views 27 replies 5 participants last post by  jadnashuanh 
#1 ·
As I mentioned in another thread, I'm considering a wiring harness/interface kit for my vehicle's bike rack so I could hook up a trailer and get rid of the PDC alarms when I've got my bike rack installed. In the UK, they require a light board that duplicates the tail/brake/turning if a bike rack obscures the existing vehicles lights. And, they typically use a light board and an extra license plate to comply with those requirements.

I located a company (Right Connections) that makes an interface kit for the GT that maintains the factory functionality: disable the PDC, provide zoom for the camer, and enables the stability program for a trailer. It's available with the traditiona European 7-pin or the newer 13-pin connectors.

To convert either to a US trailer connection isn't all that hard and there are adapters available, or you can make one if you're handy.

The 13-pin connector plug is a twist/turn waterproof connector which seems like a much more reliable connection that the default US 4-pin flat connector, so I'm leaning on getting that harness.

I can buy a light board with either plug already on it for about the same price (need something plugged in to inform the car there's a trailer there), and a second set of lights back there wouldn't hurt.

You can purchase an interface kit that will make the lights work, but I've not found any other one (since BMW does not provide a factory hitch for the GT in the USA) that enables all of the stock functions other than the one from Right Connections in the UK.

Anyone have any experience with these things and suppliers or have any suggestions? ANyone have a trailer hitch installed on the GT (In the USA) that has the factory functionallity enabled? If so, how did you do it?

Thanks...
 
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#2 ·
Harness interface options

In investigating getting a wiring harness for my vehicle, assuming I'm interpreting things properly, I've found some interesting gotchas.

My vehicle, and more and more of them, are now using a high-speed serial bus to interconnect and control various functions and items in the vehicle. IOW, the computer is becoming more and more integrated into the thing, making conventional thinking and slapping something in harder and harder to do. This allows the manufacturer to not need as many wires running to things, as the serial bus (databus) can tell a smart device what it needs to do and when. It makes it harder to understand and add to, though.

As this relates to the wiring harness for integrating a trailer, it brought up two possible ways to do it. If I got this right, for the lighting functions: turn signals, brakes, running lights, backup lights, etc. at the rear, there are NO power lines to control them from the front turn signal switch...they use the CANBUS, a high speed serial databus to talk to a module at the rear which then generates the power to actually turn the things on and off. It also has logic in it to detect whether the thing is drawing current, and if not, uses that to then send a message to the computer saying that the thing did not turn on when requested which should initiate a bulb out warning.

Since the logic is only designed to handle the 'normal' load of the designated lamps, just tapping in and powering additional things to a trailer would likely overload the drivers so a different method must be employed. Those interface kits fall into two categories: smart and dumb. The factory one is smart in that it also gets patched into the CANBUS and then can tell the computer that there actually is a trailer installed, and that smart interface provides its own drivers for these additional lights. BMW doesn't sell a factory interface kit for my car in the USA, and the one they do sell for the rest of the world is not readily available here. The place I found in the UK makes a compatible version, and that's what I'm toying with buying. The ones that are available in the US are still sort of smart - they don't load the factory lights, but you need to find and clip into all of the desired functions, then when the car's module turns on a light, that high voltage then triggers the module to output 12v to activate the trailer lights - IOW, the trailer is not drawing current from the car's lights in parallel, but through the module direct to the battery via a fused link. Since it doesn't talk to the car's computer, it has no way to know you've actually got a trailer connected, and thus does not turn on the trailer stability program, enable the backup camera zoom function, or turn off the rear parking sensors. I find that last bit the most annoying. And, actually, since the smart version does not need to connect to as many places (in theory, it could live with just the CANBUS, power, and ground), it's faster and easier to install. But, as emergency backup, this one anyway, hooks to the center brake light and the right turn signal driver line. The factory guy told me that they do that in case the CANBUS dies, it can still light the brakes, and it uses the right turn signal and the center brake light line to determine that you've turned on the emergency flashers. All kind of neat and scary at the same time!

Anyway, the trailer hitch company guy told me that they're getting closer to finishing the negotiation with BMW to be able to provide a true factory, plug and play harness, but it has been taking much longer than they'd hoped negotiating all of the hoops. They're confident that they'll eventually be able to provide it, but in the interim, I'm toying with getting the Right Connections harness. This might require the use of a dongle to get to a US trailer connector or to cut off the factory one and splice in on, but that stuff is readily available.

The UK has historically used either one or two 7-pin round trailer connectors. A simple trailer uses one, a caravan (travel trailer) typically would require two - the second one providing caravan battery charging and frig power. The rest of Europe has been using a single 13-pin plug to provide all of those functions in one nice, waterproof, twist/lock connector and you can order the Right Connections harness with either one. I'm leaning towards the 13-pin connector as I like the idea of twist/lock and waterproof in something that gets exposed to that nasty environment under/behind the car. It's not that hard to build or buy a converter dongle, if you don't care to modify your existing trailer or need to borrow one.

I'll keep you updated, should I go any further, with results.

If I'm interpretting this all wrong, please set me straight!
 
#3 ·
US Spec GT and Trailer harness

Has anyone with a US spec GT with a trailer hitch installed gotten the OEM factory trailer functions to work? IF so, how did you accomplish that.

I'm going to try to find out if the programming in the US spec vehicles will recognize an appropriately designed CANBUS interface module and act like the European vehicles and simply recognize it when a trailer is installed. I'm not talking about a trailer harness that does not talk on the CANBUS, but one that does. The X-series, I'm told, but do not know, work that way...install the harness with the appropriate module, and it just works, no extra programming required. It would be nice if the GT did as well!

I'd like some confidence that purchasing a kit from Europe will work, as the dealer tells me they have no way to reprogram the car to recognize it, and has little incentive to do it either.
 
#4 ·
Well, this sounds like I'm talking to myself...lots of viewers, but no responses!

Anyway, in further investigation, I was told that the Right Connections trailer interface wiring kit once installed (on a UK BMW anyway), does NOT require any recoding of the vehicle, and provides all of the factory trailer functionality: PDC off when a trailer is attached, enable vehicle trailer stability program, and makes a zoom with centerline video function available. They have no way to verify the same would happen to a US spec vehicle, and thus, I'm a little leary about buying it.

I also found and read the trailer installation instructions on the BMW X3, and the last step there says to reprogram it. The BMW wiring kit is nicer, since it just plugs in.

Anyone have a trailer hitch installed on their GT? Do you have a trailer wiring kit installed? Do you have any of the factory trailering functions? Are you in the USA or elsewhere? Did you have to reprogram anything?
 
#6 ·
Execuhitch are working with BMW to become an OEM supplier...just not sure when all of the details will be worked out, but they tell me it is progressing. In the interim, I was trying to get a wiring harness that would provide the OEM capabilities inherently available in the car. The biggest issue right now is with the bike carrier, the PDC is always screaming at you when in reverse, and for a few seconds after you start moving forwards, too. Plus, all of the red boxes mean you have trouble looking through the bikes to actually see much. For that reason, even though I'm not likely to pull a trailer (often, or at all), I'm interested in the wiring harness and maybe a light kit as used in parts of Europe, to make the vehicle think there's a full trailer behind.
 
#14 ·
The biggest issue right now is with the bike carrier, the PDC is always screaming at you when in reverse, and for a few seconds after you start moving forwards, too. Plus, all of the red boxes mean you have trouble looking through the bikes to actually see much.
I was re-reading your older posts. Btw you do know that you can turn off both the pdc there's a switch in the center console, next to the shifter and the (annoying) red boxes with one of the options in iDrive while in backup camera mode...I've always had them off since I find them annoying even w/o stuff in the back...
 
#7 ·
Programming line items

I've been searching a bit on programming a vehicle to run with a trailer and found a few s/w switches in the computer:

-there's a few for different countries trailer modes (not sure what that does!)
-there's a switch to turn off the PDC when it detects the trailer line (not sure what the trailer line is!)
-there's an adjustment of how often it searches for the trailer module (default may be off)
-there's an adjustment of the PWM value

If anyone's played with this, I'd be very interested to hear your results.

I did order a cable so I can program things. Still need to download and learn how to run the software...going to take this slow since I don't want to make the vehicle undriveable! BTW, there are thousands of settings that can be tweaked. I'm sure there aren't too many that a user should consider changing, though.
 
#8 ·
Well, seems the stars aligned, and I scored an OEM (Euro) BMW wiring harness and interface for my car. It has the Euro 12N plug on it rather than the preferred (by me) 13-pin DIN plug, but I can live with that. Now, hoping that the get ready is on the USA cars! Basically, if it is, there's a single harness with two plugs on it that go to the vehicle connected to one for the trailer plug. Then, the interface box gets mounted and it plugs into the existing plug. You have to mount the trailer plug. Other than cable tieing things in place, and reprogramming, it's done! Real slick, not cutting/patching of the exiting harnessess - just plug and play.

I may not have the bracket to mount the trailer plug for a couple of days, but I'm going to try to see if the plugs are there in the harness, waiting for this...here's hoping.

Still looking for someone that knows what needs to be changed in the software to make the system recognize the new box. Some models supposedly recognize it automatically (like the X3), but the instructions say the F07 needs reprogramming.
 
#9 ·
Well, bad news...in the USA, the GT does not have a factory trailer hitch option therefore, they do not install the prep so there's no plugs to plug the kit I have into and no wiring diagram to try to figure out how to splice it in. Not sure what I'm going to do, and may end up just living with the alarms when using the bike rack. At least, up to this point, it hasn't cost me anything, and I do have the most expensive part, the interface controller box.

If anyone has any thoughts, I'd sure welcome hearing from you.
 
#10 ·
I've got this Euro OEM BMW F07 trailer wiring harness/interface kit that, if the factory vehicle wiring harness is prepped for it, will literally just plug in and perform the trailer functionality (well, you have to program the car to recognize it afterwards). BUT, USA delivered vehicles, do NOT put that prep in any vehicle that does not have a USA approved trailer option from the factory...mine, does not while it is available most anywhere else in the world.

So, I've got this interface box designed to plug into the vehicle into an existing plug - no pinout documentation (since it's supposed to be just plug-and-play), and without it and a mating plug to wire up my own, currently useless to me! The actual trailer connector harness also plugs into factory sockets, but those functions come from the module, and if I can find out the pinout, I can handle that connection by cutting off the existing plugs and wiring it into a new one.

I'd like to know if anyone has the wiring diagrams that show this connection. If so, I should be able to cobble up how to interface it into my car.

My alternative is to try the Right Connections kit, but they will not guarantee it will work on a USA model (likely it would, but I don't want to buy one, install it, and find out it won't!). The Westfalia harness probably would also work, and may use the same Hekbako interface module, but I haven't looked into that one much, yet.
 
#11 ·
For those of you outside the USA

If you have a GT not made for the NA market, would you take a look behind the bumper cover near the left side exhaust pipe and see if there are a couple of plugs tucked back up in there? They should have dummy caps in them to protect the pins/sockets. These are for installing the factory trailer wiring harness. If those exist, there should be another one under the floor of the trunk to capture the trailer interface module.

I'm curious which markets have this prep in their harness. I have an OEM kit that is designed to plug into one so prepped, but it does me little good, since those plugs don't exist in our harness, and the NA BMW group can't get the prep package (nor do they make any towing options available on the GT here). I've been trying to get the pinout of the module, but to no avail, so I could cobble up a harness myself.

I'm going to be in the UK on Monday, and may try to either pick up an interface harness kit and maybe look at a vehicle there myself. I'm hoping, if I buy one there, it will work in my vehicle as I'd really like to turn off the PDC blaring at me when carrying a bike rack. I'll pick up a trailer plug so I can make an adapter should I want to actually tow a US trailer and need to connect its lights.

If I had a bicycle rather than a recumbent trike, I'd bite the bullet and get their roof-mounted system (which is available here), but that makes it impossible to drive into the garage or even park near my garage since there's an elevated deck above with limited height. It's just so much quieter and easier to just tuck it on behind, but that means you live with the PDC issue.
 
#13 ·
If it's there, I couldn't find it. It does show the part of the harness for their swiveling trailer hitch, but not the make ready of the internal harness to the hitch plug, unless I missed it. I spent a bunch of time mucking around. I did see what I think was a picture of what is needed on a Romanian site, but they did not list that callout as an available part, nor did they list a part number for it. I'm hoping I may have more luck while in the UK in the next few weeks. But, I sure would prefer to use what I have rather than buying an aftermarket kit, since the cost was right!
 
#17 ·
I just came back from a vacation in the UK and bought a Right Connections trailer wiring harness for my GT. Ordered it with the 13-pin DIN trailer connector used on most of the newer European vehicles along with an adapter and a spare plug so I could make my own adapter to the US style, if needed. I have a UK cycle light board I plan to use with my bike rack to provide the stimulus to shut off the PDC in the rear and give the vehicle a little more visual impact when carrying the trike (I carry a recumbent trike in a basket behind the car).

But, finding a 40mm hole saw in the US isn't something you can get locally, and its delivery will delay my install for a bit. Hopefully, the thing's smarts will work with the US programming or it was a big waste. It may take awhile before I get it installed, but will update once it's in with my results.
 
#18 ·
The saga continues...

I've installed the harness, still have a lot of trim removed in the hatch area, and trying to resolve a few issues.

FWIW, I recently installed the headlight switch that has the rear fog lights...the USA builds do not have that switch, but the vehicle itself is capable of using it - I plugged it in, the rear fog lights now can be turned on/off via the new switch...no coding, no additional wiring, just replace the switch.

This brings up a question: The rear taillight assemblies have four wires in their connector. The light has four functions, and I assume it needs ground (unless it gets that by the bolts holding it in). It has: running lights, fog light, turn signal, brake light. How does it get those four functions with four wires in?

Second observation and question: After installation, the only trailer signals I can get to function are turn signals (both left/right and hazards work), and running lights. I did not check rear fog lights, as the 'trailer' I have (actually a bicycle light board - if you're from Europe, you know what that is) doesn't have a foglight in it. So, it must be listening to the CANbus, or it wouldn't operate the running lights or the turn signals, but it is not operating the brake signals. The light board appears to be wired correctly.

Third question: for redundancy and certain emergency situations so you still have trailer brake lights and hazard warnings if the CANbus is off or not functioning (like say the car is off, locked, and you have the hazards on), the harness connects into the vehicle and taps the center brake light line and the right turn signal. The center brake light is supposed to be a black/yellow wire. In the location they indicate in the instructions, I could only find one black/yellow wire, but if it were operating correctly, even if the CANbus wasn't working, it would operate the brake lights. I was wondering if anyone knows any good reason you couldn't tap the brake signal at a taillight verses buried back in the harness elsewhere. If so, which lead is it at the right taillight. Someone had told me blue/black stripe, but there is no wire there with that coloration, or the black/yellow that's supposed to be the center brake light (I sort of would have expected them to all be the same color for the brake function, but hey, I didn't design it).

One of the special features of the Right-Connections harness kit is that it does not require the vehicle to be recoded, as opposed to the OEM kit. Well, it may work fine in the UK market, but unfortunately, it appears that's not true for the USA market vehicles - they would not say it would work, so I can't blame them for any issues....just wondering if anyone else has resolved this.

Now, if BMW made an OEM harness available in the USA, I'd have picked one of those up.
 
#19 ·
Update: still don't have the brake lights working, but with a trailer attached, and going into reverse, it does disable the PDC and defaults to the 'top down' video mode. I hadn't been able to play with it much, and don't know if any other video modes are available. So, without programming the vehicle, the Right-Connections harness does enable all of the 'normal' trailer functionality as the OEM version, and once I get the brake light glitch worked out, I'll be all set.

What slowed me down during this troubleshooting was the stupid cycle light bar I bought...with a nice QC sticker on it, I assumed someone had actually tested it! Well, if they had, they'd have found that it wouldn't work! The leads to both the brake bulbs were so loose, they had fallen off in shipping. THen, in the trailer plug, they'd tightened down the screw onto the insulation, not the wire. So, even after repairing that and checking the trailer harness fuses, the brake functions still didn't work. I've sent an email, and hope to get some troubleshooting tips.
 
#20 ·
Finally, Success!

I finally found the proper wire to the center brake light, hooked that up, and the thing now works! Earlier, they'd said all of the lights would work off the CANbus, but that isn't true on a BMW (but is on others). BMW has some weird, patented technique to control the lights, and a generic box can't decode it without patent issues, so that is the reason the brakes didn't come on and you must connect it to the center brake light. My guess is, the center brake light is the only brake light that actually gets 12vdc directly, the ones at the rear get some multiplexed signal that controls that cluster which is why they can make four different lighting functions work with only 3-wires and a ground lead (turn, brake, fog, running).

The OEM and the Right-Connections harness provide the following functions:
- enable trailer stability logic
- disable the rear PDC when connected
- adds a green centerline on the rearview camera screen (it's slightly offset to the left so you can still see the ball). At least, I don't remember that center line being there, only the outer ones previously.
- on the rear view camera, when connected, it shows a symbol for a trailer and does not display the proximity boxes when the PDC is active.

This harness provides a 20A, relay controlled caravan charging circuit, and a separate, always on frig circuit activated (I think) when it detects a trailer attached. The relay circuit only comes on when the vehicle is running.

So, there are four splices that need to be made, plus some connections to ground and to the battery. You connect to the right turn signal, the CANbus, and the center brake light. You must remove a lot of the trim in the rear - essentially all of the floor pieces and all along the right side to gain access to run the harness and make the connections.
 
#21 ·
Congrats JAD! It was a long road, but you got there.
It's really too bad that BMW does not tow prep the F07s destined for North America like they do the ones destined for European countries. :(
This would have been SO much simpler if that were the case. But the important thing is that you got there.

Cheers,
Daryl
daryl@invisihitch.com

 
#22 ·
Some pictures

Seems some have been having problems finding the elusive 3rd brake light connection which is needed for an add-on towing harness to function properly. The wire for the third (center) brake light runs in the bundle along the front of the right-rear wheel well. There are a couple of yellow-black wires in that bundle, and the one you need is the smaller gauge wire. The picture isn't all that clear.

The other pictures include one of the harness's power connection next to the battery which includes a stack of fuses, a power relay for the accessory line to the trailer, and the actual connection to the battery itself. Another one shows the Right-Connections module which fit in a tray underneath the first aid kit after removing that trim. Depending on your vehicle, you may have some of those spaces filled with other CANBus modules. And, there are at least several CANBus twisted pairs you can tap into along the back of the wheel well. Then, I included one of my vehicle parked at the trail head of the local bike trail. It's a little over 12-miles through the woods, part of it next to a river, and through some conservation areas that I try to ride every other day once the snow is off the trail. I have been averaging a bit over 2K miles/year, mostly on that trail. Goes by some ponds, and each spring, some geese fight you for the trail with their goslings, which are interesting to see growing up. I've had a deer cross the trail in front of me (almost ran into it!), along with one eagle, a few hawks, and various other things...it's a nice path, and not very busy during the week. It's a pain on a nice weekend, but being retired, I can avoid those most of the time!

Anyway, a couple of other things you may notice: living in the snow and lots of sand and crud on the roads, I opted for the mudflaps. Also, I have tinted the windows with a 3M, top-of-their-line material...it's not very dark, but does a fantastic job of blocking UV and IR (something like over 200 layers of material in the sheet!). It's the only one approved by the National Cancer Society for UV protection, and gets used a lot on ambulances and emergency vehicles.
 

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#23 · (Edited)
in that bundle, and the one you need is the smaller gauge wire. The picture isn't all that clear.

The other pictures include one of the harness's power connection next to the battery which includes a stack of fuses, a power relay for the accessory line to the trailer, and the actual connection to the battery itself. Another one shows the Right-Connections module which fit in a tray underneath the first aid kit after removing that trim. Depending on your vehicle, you may have some of those spaces filled with other CANBus modules. And, there are at least several CANBus twisted pairs you can tap into along the back of the wheel well. Then, I included one of my vehicle parked at the trail head of the local bike trail. It's a little over 12-miles through the woods, part of it next to a river, and through some conservation areas that I try to ride every other day once the snow is off the trail. I have been averaging a bit over 2K miles/year, mostly on that trail. Goes by some ponds, and each spring, some geese fight you for the trail with their goslings, which are interesting to see growing up. I've had a deer cross the trail in front of me (almost ran into it!), along with one eagle, a few hawks, and various other things...it's a nice path, and not very busy during the week. It's a pain on a nice weekend, but being retired, I can avoid those most of the time!

Anyway, a couple of other things you may notice: living in the snow and lots of sand and crud on the roads, I opted for the mudflaps. Also, I have tinted the windows with a 3M, top-of-their-line material...it's not very dark, but does a fantastic job of blocking UV and IR (something like over 200 layers of material in the sheet!). It's the only one approved by the National Cancer Society for UV protection, and gets used a lot on ambulances and emergency vehicles.
I am not the outdoor bike enthusiast that you are but I can identify with your rationale for the mudflaps as I some distance to the west of you. For those pondering mudflaps I belive they come only as black, unfinished rubber and need to be painted to match GT's body colour.

I also agree with tinting windows but I am not sure if mine was 3M (but I will inquire). In my opinion any tinting is better than no tinting at all.

Sent from BimmerApp mobile app
 
#24 ·
The OEM mudflaps come in primer, and the instructions say that they MUST be painted. Since they are a plastic, I suppose they might not be harmed by not putting a finish coat on them, but they probably would not look very good for long. They aren't all that hard to install by yourself, but because they are slightly flexible, they need the same paint and prep as a bumper, which isn't likely something you could do for yourself and have it last.

There aren't that many places, relatively speaking, that sell that 3M tint. 3M will only allow certified, trained shops to install it, and not that many feel it is worth their costs and effort even though the install process is the same as most others. It's really hard to compare one verses the other, but the reviews of that product are good, along with the American Cancer Society's approval - no other product I've seen has either sought or gotten that. http://solutions.3m.com/wps/portal/...me/Products/WindowFilm/CrystallineWindowFilm/ Mine doesn't block much visible light, but enough to take the glare off, and not lose any visibility at dusk for the most part, and is legal everywhere on all windows, including the windshield (I don't have my windshield tinted, though). It does a major job of keeping the internal heat down, and has great UV protection, but the effects on that take awhile to show benefits.

But, back to the hitch and harness...in the USA, the RightConnections solution is the only one that will get you the OEM functionality of the choices out there. The actual OEM kit won't work without the prep (not done for vehicles sold in the USA) and even if you did manage to get that to work, you'd still have to find a dealer that would program the box to make it work. The Westfhalia (they make the OEM one, but sell an aftermarket version as well) still needs to be programmed, and the USA dealers either won't or can't, so you're stuck IF you want the OEM capabilities. You CAN get the light functionality with one of the readily available kits, but it will NOT enable the stability control, the camera view, or disable the PDC in the rear. All in all, I think the solution I found is the best for what I wanted to do.
 
#25 ·
The OEM mudflaps come in primer, and the instructions say that they MUST be painted. Since they are a plastic, I suppose they might not be harmed by not putting a finish coat on them, but they probably would not look very good for long. They aren't all that hard to install by yourself, but because they are slightly flexible, they need the same paint and prep as a bumper, which isn't likely something you could do for yourself and have it last.
I had to order the flaps after I took delivery and actually had them in my possession before they were installed during a follow-up visit. They felt, looked, and smelled like rubber but there may have been a primer on them. As they were black and my body colour was Black Sapphire Metallic I drove with them for just over a year before I had my accident. During the restoration, they painted them for me for free (given how long it took), a saving of around $250 CDN.
 
#26 ·
They're each made in two parts...the inner part doesn't get painted...only the outer part, and they're held together with a bunch of screws. Then, the whole thing gets screwed to the existing fender well, only using a few of the original screws. The hardest part of the install is getting the cuts for the c-clips nice and neat for the screws that are added. I found that it works best to actually cut a small rectangular slot, rather than just a slit - then, the c-clip will lay flat.
 
#27 ·
Hi JAD,

Thank you so much for this long "self dialog" and post on how to hook up the wiring harness. I just bought my wife a 2012 550xi GT and we need a trailer hitch for it. I ordered an Invisihitch with their wiring harness and it arrived yesterday! yeah! I'm waiting to install it until the mud flaps arrive, and a can of white aerosol paint, then I will take it all apart at once and install all at once. Although the mud flaps could go on after. I read the install directions from the link you posted, thank you for that by the way.

I have been emailing Right Connections and they say their harness won't fit in the Invisihitch plug mount. I don't care, I'm handy like you are and can find a 40mm hole saw, or Dremel if I have to! So my questions to you, if you please, are how much did it cost, and do you know where I can purchase one from? Then I will really bother you with questions! Although these posts and pictures are great. I researched 13 pin down to the US 4 pin adapters which are available. If I adapt to a 4pin flat, will the CANBUS still recognize a trailer?

The other thing is I need this by August 7th as we are taking a UHAUL from Michigan to Florida and I really want the stability logic to be activated. Which it won't be with the standard wiring harness from Invisihitch.

Thanks JAD and I hope to hear from you soon.

Dan
Michigan
 
#28 · (Edited)
One of my brother-in-laws is working in England, and I purchased the harness from a local shop there while visiting. THey were able to get it without VAT because of the government contract terms for US government contractors. The corporate offices do not sell direct to individuals, so you have try to deal with a dealer, which makes it harder. This was 3 years ago now, but I think it ended up costing me about $180 or so - worst case, that was in BP. Not cheap, but the only way in the USA to get all of the features of the OEM setup. Not all places are willing to deal with the paperwork to avoid the VAT, so that would add (I think) 19% to the cost.

It should detect that a trailer is plugged in when using an adapter as the logic looks for current draw. I bought a converter but have not had a reason to use it, so I never wired it up...IOW, I can't tell you for certain.

Some people try to get the harness through one of the existing rubber grommets, but IMHO, I think it would be nearly impossible to get it sealed well. As it turns out, the holesaw they call for seemed to be a bit big, and a US fractional one maybe slightly smaller than the 40mm would probably work. There are plugs attached to both ends of that harness, so unless you removed one, you'd not get it through the hole with an existing harness. The new harness has the grommet installed over it.

I chose to mount their connector by making a plate with a hole the proper size to hold their thing. THen, I carefully measured and used a holesaw in the black plastic underneath the car such that that only the cover is below the cover. With it all being black, it's really hard to get a decent picture, especially without it being up on a lift.
 
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