Wiring Harness Conversion - U.S. to European

Send a PM to Andy Germany, who has advised on this course of action to another reader recently.

If you can, tap into the switched lead from the brake light switch. That should be fused, then run back to your trailer connection. The trailer is not wired for an electric trailer brake, so that should free up a wire in your VW. If you can find the VW trailer brake wire in the front of the car, disconnect it from whatever was sending a signal to it. Then you can use that wire to send the new brake light signal to the trailer plug at the back of the car.

The specifics of the European trailer plug is beyond my knowledge. Good luck, or contact Del.

this might solve the stop lights, but the turn lights will still act as stop lights and turn lights.

Geir

This thread may help...

http://cr4.globalspec.com/blogentry/9400/DIY-Trailer-Hitch-Wiring-Challenge

Can you first post a picture of the rear lights on the trailer?

Does the car have US turn signal/brake lights? Or have they been made European?

Your VW dealer is a complete "Ars**le".......

Does the car need to be kept US standard for later return to the USA?

Can you wire correctly and safely if given a schematic?

These are the European trailer lamps I have installed on the trailer. Three separate clusters of led lamps each:

1. Running lights

2. Stop lights

3. Turn lights

The trailer works perfect on another car when I tested it.

My car (the VW Tiguan) has not been modified, but as far as I can see the US version is identical to the European with separate red stop lights and yellow blinkers. Only the wiring harness of the trailer hitch is different.

The car will not go back to the US again. I am here to stay, so is the car.

If I had a schematic I would be able to complete the job. An alternative would also be to go to a garage and have them do the installation (not to the local VW dealership).

A simple way to do this is to pick off the relative wires in the back of the car, via a fuse each time and feed them to a 7 pin socket.

How good are you at wiring? This is a simple job really.

For brake lights use a 8 amp fuse, it gives a bit of leeway for you, for others use 5 amp fuses....wiring a led with a dropping resistor over each fuse will tell you immediately if one is blown...

May I ask if you have a multimeter and the relevant tools?

I know it will not be possible to connect to the tail lights of the car. The light unit of the car will not "allow" that and simply not give any output. It has to be run through the trailer hitch control unit. Either I am able to use the existing US unit and somehow split the stop/turn signals, or I have to install a European unit and accept the cost.

Below you see my best suggestion so far. Here I use 4 relays.

The problem here is that if the stop light and one turn light are on at the same time, the result will be stop lights and the opposite turn light active.

So your car has US style brake/Turn lights......that could be a problem......please confirm.

No, the car has European turn and stop lights. Only the trailer hitch control unit is US and has combined turn/stop output.

Then we leave that out of the equation, simply remove it.

I was able to buy a trailer light convertor such a you describe from my local auto supply for about $35. It is a small device that wired directly into the car rear light harness and the outputs go to the trailer. However there is not a 7 pin config for trailer brake and 12V acc. on this device. These would have to be wired in from your vehicle. I would recommend getting the brake light adaptor and then wiring it and the other circuits that you need into a 7 pin recepatcle yourself. Do try the local auto supply store this is a common device. I'm sure that you will be able to figure out how to add the other 2 circuits to a common 7 pin receptacle once you see the thing.

Hi Geir,

I'm a bit confused about your wiring code for the European plug. I think it might be a Norwegian spec. I checked my own trailer which is French built and approved by the Spanish transport authorities it coincides with the diagram I picked from http://www.tridenttrailers.com/trailer-wiring-diagram.htm for Britain.

However, assuming the pins you have given us are correct for your trailer then the simplest way to solve it is as Andy says except, to avoid the lamp-check module in the car showing a fault with two lamps in parallel you power the trailer lamps via vehicle type relays. These should cost no more than a few kroner each. I have shown four relays but actually you do not need the tail lights relay as your present wiring runs these same lights. Your present system probably checks for failed lamps in the trailer, that feature will be lost of course. Always remember to check all the lights at the time of hitching up. You will need a european lamp cluster of course. If you cannot get them locally then the link above should have them.

The electric brake could be connected via the spare pin 7 but be careful, I have never seen electric brakes used in europe, You should check with your transport authorities as to their legality. Remember, if you have an accident and your vehicle is not legal your insurance may not cover you.

I hope this helps

Chas

GA from me, you have supplied excellent infos.

Did I miss something previous, electric brakes? (I know the USA has them, but I did not realize that you could use them in Europe...)

If allowed here, surely they can use the brake light signal/power??? Just a thought!

Yes, the trailer hitch has a connector for electric breaks (one of the 7 pins). I am not sure it this is 0~12V or what. I have also thought of using this for the stop lights, but don't know how the electric system of the car will react.

The trailer does not have electric breaks. When I used the trailer in the US I simply had to use an adapter which only connected 4 of the 7 pins to a flat four pin connector at the trailer. One of the "missing pins" (see picture below) would be the electric break. This caused no trouble with the car electric so I assume it will not be a problem to just not connect the electric break pin. The car will assume the trailer does not have breaks and all will be good. This is the reason I believe the best solution is to split the stop/turn signal and leave the break signal as it is. Still all will be good with a European trailer with hydraulic breaks.

I know it would not be possible to have a trailer with electric brakes registered in Norway. I assume these rules apply for all of Europe.

Does your trailer have "over run" mechanical brakes (I personally have never seen Hydraulic brakes on a trailer) or no brakes at all?

It has no breaks at all. It is a small trailer.

Perfect.

Some of my other questions I believe you never answered, could you do that now please ? (to do with wiring knowledge and tools)

Yes, I have the proper tools (including a multimeter) and will be able to complete the job if given a wiring diagram, but as I indicated I may ask a garage to do the job for me if it implies extensive work. I hope this answered your questions.

I see no problems in picking up the signals at the back of the car, passing each one through a fuse and supplying the socket......you bought LED lights and these will not use much current, that was a great purchase.....

Have you obtained a wiring diagram yet or shall I post one.

Buy heavy duty cable for cars of the correct colors.....

Buy those special plastic clamps where you can "T" off from a cable easily.

Buy inline fuse holders. Plus spare fuses.

I would do the job myself, its really easy.

Remember to remove Battery + when working AFTER you have identified both sidelights, brake lights, fog light, both indicators and a good ground. Mark them carefully, check with a meter or 12 volt bulb to ground.

Look here for the connections and wiring colors:-

http://www.tridenttrailers.com/trailer-wiring-diagram.htm

Follow the numbering and color system carefully!

This should help, ask me and CR4 if you need further assistance on anything.

Regarding connecting directly to the car tail light, I know this will not work. The car electronic will not allow this. This is the reason the car is equipped with a trailer hitch control unit.

With LED lights, I would be most surprised if it did not work correctly. Why not try it out first, its only 1 wire and a ground return.....try the brake lights first.

There may already be a device similar to this that was installed to allow your 5 wire system to work with a 4 wire trailer system. If you can find this, it may have the brake light wire connection you are looking for. Good luck.

Taillight Converter - Utility Trailer, Allows Vehicle w/ Separate Stop & Turn Signals to Tow Trailer w/ Conventional Combined Lamps
Front	Part: BK 7551086 Product Line: Balkamp
	List Price Your Cost Unit : : : 17.57 14.09 Each
	Qty
Features & Benefits
For Repairing Damaged Taillight Converters
Attributes
Product Application : Allows Vehicle w/ Separate Stop & Turn Signals to Tow Trailer w/ Conventional Combined Lamps Contents : Electronic Tail Lamp Converter Converter Wire Configuration : 4-Wires to Car Side & 3-Wires to Trailer Side How Installed : 4-Wires Spliced Into Vehicle's Stop, Tail & Turn Signal Wires, 3-Wires Spliced Into Trailer Connector Per Instruction
Warranty The connection with the seven connectors that you are showing, is refereed to in the US as a RV (recreation vehicle) connector.
1 Year

I am trying to go the opposite way. My car's trailer hitch wiring harness is American, and has combined stop/turn lights. (The car tail lights however has separate stop and turn lights.) Combined stop/turn lights is neither allowed in Europe for cars nor for trailers. I need to split this to be able to connect a European trailer with separate stop and turn lights.

If your car was manufactured with amber turn signals in the back, it is Already wired for the European trailer configuration. At some point the car was modified to use the US design trailer configuration. If you follow the flat four wire plug for the trailer that you have now, you may find a device similar to what I sent. If you go to the IN side of the device, the trailer wires you need for your new trailer should be there. Thy to see where the trailer plug leads to.

As the average car owner here gets less inclined to do wiring work on his car, the aftermarket people have developed adaptors that connect to the car's existing wiring harness at the back of the car. These adaptors allow one to simply unplug a factory connector and ad an adaptor to the car, and then plug the original connector back in. This then leaves a pre-fabricated trailer plug for use.

An example is shown below. This one is designed for use on Ford products. Note the heavy red and blue wires that are not connected. They would be used for trailer brakes, and battery live, blue and red.

I thought you had changed to European brake and indicators lights....is that still part of the job? (its still easy, just some wires will be longer and less easy to find the correct connection.)

I was under the impression that you had European rear lights on the car already.......

Note for any one else coming to Europe, DO NOT BRING A CAR, BUY ONE HERE.....!!!

There was no reason to change the tail lights of the car. A lot of cars in the US have separate turn/stop lights. The US and European VW Tiguan tail lights are identical. Also the position light (yellow side lights) are now allowed used in Europe, but they are not mandatory. Hence these lights did not have to be removed.

I do not agree regarding not importing a car from the US. I saved a lot of money by buying it over there, and still if I end up paying $2,500 for a new trailer hitch, it is a lot cheaper than buying the car here. You just need to know what you are doing so you buy the right car.

Agreed....

I have had some US friends with cars that are NOT sold in Europe run into REAL problems here. Yours is most likely made here and then exported....but VW Golfs are made in the USA and it is next to impossible to get them registered in Germany.....its a different car under the skin, or at least it was some years ago....

I forget that the UK has a far more humane approach to such things!!

Below is a picture of the US connector I had at the trailer:

Hi Andy,

Yes, it might be possible to use the electric brake power directly for the lights but, without knowing the car electrics we cannot know if there is a check system on that also. Many cars have quite sophisticated electronics in the system checking for things like blown/shorted bulbs. This can be achieved either by a shunt in the circuit, which seems to be the favorite with the auto industry or with current operated relays which we find commonly on boats.

It is possible that he will get a brake failure warning if the electric brake circuit is not connected since he still has the US trailer electric system in the car.

Slightly off topic, can any of our American members explain the electric braking systems commonly used in the US? (not the possible systems, we can all think of ways to achieve a system, rather those actually in use).

Regards

Chas

The brake circuit on trailer brakes can consume a fair amount of current. Using the brake light switch to power the brakes can over power the fuse and possibly the brake light bulb sensor circuit in the car. The correct trailer brake controler will send a proportional signal to the trailer brakes. This allows the trailer brakes to be applied at a gradual rate when applied.

Looking at the pictures, he has bought LED rear lights, with a bit of luck, the load will be minimal. I do not expect to see either over loads or other problems, that was a great purchase I feel.

The load is from the trailer brakes, not the brake lights. The trailer brakes use an electric magnet to try to grab a steel plate that spins along with the brake drum. The twist of the magnet trying to turn causes the brake shoes to be driven against the drums. How are brakes activated on European trailers?

Not with electricity.

The brakes here for trailers are "over run" mechanical brakes, but the trailer in question is unbraked anyway......

How are the "over run " mechanical brakes activated?

I am having a hard enough time writing, do you expect me to read now also?

The trailer compresses a heavy pin in the hitch and then presses on a mechanical system that over thick wire ropes, activates each brake drum......

Look here for some good pictures that you can "activate".

Thanks for your details. I have never seen a system like that here.

There are some trailers that have a similar system here. They are referred to as inertia brakes. There is a master cylinder mounted to the trailer hitch of the trailer. As the trailer tries to push the trailer hitch under breaking of the car, the master cylinder piston is pushed into the master. The master cylinder has two brake lined running to the trailer wheels. The trailer wheels are fitted with either drum brakes, or more recently, disc brakes. The wheel setup is similar to what would be found on the rear of a standard car.

I guess I missed the line about no brakes on this trailer.

On some American trailers a separate signal is sent to the trailer to activate the trailer brakes. When the brake switch is used for this, brake switches usually burn out after having the brake light fuse replaced with a higher amp one.

hello/

Geir can write me how you solved the problem with a hitch (5N0055204NA )in the VW Tiguan? I have exactly the same problem.

IN VW service man switched with computer (VAG) hitch option : from North America to Rest of the world. But i sill have problem with the lights on my hitch. I have 7 blade pin connector on the car and European Standard Trailer Plug 7 WAY PIN ( I'm using adapter to connect them). How i can fix it? Thank you/