Towing Electrics US - UK

Reyllock

Member
A little problems solving for any budding auto electricians out there. I am due to import a 2011 HL BH3585RL. when it arrives at the port I will be collecting it, and towing back to home, on a British truck (rig). Our rigs are fitted with 12v Sockets, so voltage not an issue, the US tow electric plug differ from the UK type, as does the wiring (see blow)

US Plug
pin 1 - white - ground
pin 2 - blue - brake
pin 3 - green - clearance lights
pin 4 - black - charge line
pin 5 - red - left turn
pin 6 - brown - right turn
pin 7 - yellow - aux

UK Plug
pin 1 - yellow - left turn
pin 2 - blue - fog light
pin 3 - white - ground
pin 4 - green - right turn
pin 5 - brown - right side and tail
pin 6 - red - brake/stop
pin 7 - black - left side and tail

in order to meet our legal requirement in UK/Europe I will be modifying the trailer by adding amber turn lamps, and combining the red tail lights with brake lights, once I get it home!
As a quick fix, just to get the trailer from the docks to home,
Your problem is: fit the UK plug to the US wiring to give working lights (Our brake controller run on the UK blue wire as we don't have fog lights wired)

Answers to this brain teaser welcome
:confused:
 

sunflower

Active Member
Why don't you hire an rv technician there to accompany you,and make the correct changes,then hire an electrician to do the rest of the changes so it is correct and insurance doesn't become a problem.
 

Reyllock

Member
Why don't you hire an rv technician there to accompany you,and make the correct changes,then hire an electrician to do the rest of the changes so it is correct and insurance doesn't become a problem.

Awww come on Sunflower, that's not a challenge is it!?? lol. An easier and cheaper solution would be to fit a trailer board (and I will be taking one). But I like to do things the hard way, then if at first you don't succeed, give up!! :)
 

JohnDar

Prolifically Gabby Member
Just to get you off the dock and home, you could make up jumpers to run between the UK socket and US plug, and secure the trailer cord to your tow vehicle so it does not pull free while you're pulling it. If the plug styles are the same, just wired differently, you can get a male cord end that you can wire on yourself.

Something like this: http://www.etrailer.com/Wiring/Pollak/PK12702.html

They also have round pin versions.
 

cookie

Administrator
Staff member
Sounds like you will have to do a little creative wiring. You will need to drop ones side of the Coroplast belly material to run a couple of additional wires. I have had to run wires to the rear in both my rigs. Not a big deal for me. In the U.S. our brake/turn signals run off the same wire. You will have to run two wires to the back. One for right signal and one for left. There are two tail/brake/signal lights on each side of the rear of the trailer. Replace one on each side with the yellow required and add you newly added wire for the signals. Use the remaining two for tail/brake lights.
Easy right?

Peace
Dave
 

Reyllock

Member
Unfortunately John, the US blade type plug and the round pin is not compatible with either of the the UK type sockets (domestic 12v & commercial 24v) Fortunately our specialist rigs have both types of sockets running both 12v & 24v. Our commercial 12v sockets run the electric brakes though the blue wire, so I can get brakes! bonus.
wired as below;

Pin 1 - white - Common return
pin 2 - black - Left-hand rear position and marker lights, rear-registration-plate illumination device 1)
pin 3 - yellow - Left-hand direction indicator light
pin 4 - red - Stop lights
pin 5 - green - Right-hand direction indicator light
pin 6 - brown - Right-hand rear position and marker lights, rear-registration-plate illumination device 1)
pin 7 - blue - Trailer braking control

The distance from the docks to our place is about a 5 hour drive, and sunset is about 4.40pm so I would like maximum lights! running lights, direction indicators and stop lights are a must, as our traffic cops are very keen bunch!

So I figure even if I change the US plug to a UK one at the docks and just run the brakes and running lights from it, and also add a UK trailer board for stop lights and direction indicators I should be pretty safe.

And did you know that in this country because of the width of the US trailers our drivers need a Cat C+E licence (truckers licence)!
 

LarryD

Member
Can't solve the entire problem, but one thing I do know, the pin 2 blue "brake" wire in the US is from the truck brake controller and supplies current to the brake magnets while the UK pin 6 red brake/stop wire is just for the brake lights. So, these are totally different so it is not as simple as hooking one to the other. The US blue wire is heavy gauge as each wheel magnet draws about 3 amps. Guaranteed, the pin 6 wiring on a UK vehicle will not be large enough gauge to handle 12 amps. As I recall, most trailer brake systems in the UK are surge brake systems mounted on the trailer. These are far inferior to today's US systems. If it is legal, you should get a US brake controller like the Prodigy installed in your truck and run a large gauge wire from this controller to the 7 pin socket.

The four critical pins from the US side are ground, clearance, left turn and right turn. You might look at the following link to convert the necessary UK pins to these 4 pins. http://www.roverparts.com/Parts/9439C.cfm As already stated, a new brake wire is probably needed on your truck and then the pin 4 black "charge line" is +12 V from the truck's alternator to keep the trailer battery charged and that is not available anyway according to the UK pin list.

So, for a short trip home, there are really just 5 wires to the trailer, the brake wire and controller for the magnets and the 4 main wires. You can do w/o the "charge line". That is from the US perspective, not sure if having fog lights is critical initially to meet UK requirements.

I found this in a gov. UK fact sheet re: American trailers

"7. Override coupling
Caravans and trailers with an override coupling must be equipped with an automatic device
that permits the combination to be reversed without the brakes generating a braking force.
American “5th wheel” type caravans are classified as semi trailers and, as such cannot use
an inertia (override) type braking system. The operation of the towing vehicle’s braking
system must directly operate the brakes on the trailer and electrically controlled systems are
permitted."

I believe this means a good American brake controller mounted in the tow vehicle is sufficient for stopping that new Big Horn.

Hope this helps.
 
Last edited:

jbeletti

Well-known member
Reyllock,

Consider reaching out to user called heidi72 on this forum. They have not been active in a couple of years but they did import a Landmark Grand Canyon to the UK a number of years back. Think they were near Herfordshire.

They may be able to share their compliance modifications. Click the link above and send them an email.

Jim
 

JohnDar

Prolifically Gabby Member
Even though our 7-pin add-on terminals are not the same as yours, do you have suppliers over there that might have a similar item?
 
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