USA 7 Pin Round Brake Controller Wiring

It's absolutely wired into the socket, the interior termination for adding a brake controller is found under the right rear seat, you'll find all the wiring you need to tap into.

From the notes I have, they are all blunt cut (there are photos in other threads); Yellow/Red is power, Black is ground, Violet/Orange is the signal, and Grey is the control wire

Wires under the back seat

Thanks to @ScottnAZ and @anand for the rapid replies and link to the post with photos. Awesome sauce. At least someone was thinking of this when they wired the Grenadier up

nodric said:

Exhausted searching for this, so if I missed it let me know. USA 2023/24 spec has a 7 pin round trailer electrics connector. Pin 2 should be a lead that is wired for trailer brakes, but given there is no brake controller fitted stock I am wondering if this lead is wired in the socket, and if so what for, and where it is terminated inside the car? The idea being to find that termination and connect it to the brake controller to avoid running wires to the socket and butchering the socket wiring.

If this makes sense to you and you have done this I'd be happy to learn how. It seems if it is wired then cutting it and splicing to the brake controller will provided the needed brake control for electrically braked trailers.


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Don't US vehicle have fog lights? Sorry rephrase that, don't US trailers have rear fog lights? They are mandatory on all trailers in the UK and EU

Eric said:

Don't US vehicle have fog lights? Sorry rephrase that, don't US trailers have rear fog lights? They are mandatory on all trailers in the UK and EU

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Not at all

The US doesn't understand the purpose of rear fog lights, thus why most manufacturers either don't offer them on US-bound vehicles, or if they do, they have added one on the opposite side so they have dual rear fog lights. Decades ago, when most US-spec Euro vehicles had the traditional rear fog on the driver's side, countless people got pulled over and given citations for having "a light out".

Now that most of the remaining Euro brands that still have the rear fogs on their US cars are dual rear fogs, people treat them like front fog lights, and turn them on in normal (non fog) conditions.

In the US trailers are only "required" to have tail (running) lights, 2 brake lights (which almost always run double-duty as turn signals, as we almost always use red rear turn indicators), and depending on their width and/or length may require a few extra running lights along the side/rear. No rear fog, no reverse lights, etc.

We have 2 different trailer hook up connections, either a 4 pin (earth, tail lights, L brake/turn, R brake/turn), or a 7 pin (earth, tail lights, L brake/turn, R brake/turn, reverse, trailer brake activation, and 12v positive supply).

Eric said:

Don't US vehicle have fog lights? Sorry rephrase that, don't US trailers have rear fog lights? They are mandatory on all trailers in the UK and EU

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Being a Brit I hate hate hate fog lights, mainly as endless drivers think they should turn on 21w bulbs in the rain, or simply forget to turn them off when the odd foggy day has passed. It's a blessing not to have them here. The unwritten rule in the states is we turn on our hazard lights in poor visibility. We at least remember to turn them off again.

Now, the lack of reversing lights has always bemused me.

nodric said:

The unwritten rule in the states is we turn on our hazard lights in poor visibility.

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Depending on where you are in the country, there's also the unwritten rule of turning hazard lights on in a light drizzle and slowing to 20mph below the speed limit

nodric said:

Being a Brit I hate hate hate fog lights, mainly as endless drivers think they should turn on 21w bulbs in the rain, or simply forget to turn them off when the odd foggy day has passed. It's a blessing not to have them here. The unwritten rule in the states is we turn on our hazard lights in poor visibility. We at least remember to turn them off again.

Now, the lack of reversing lights has always bemused me.

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Trailers under 750kg, ie unbraked, don't require reversing lights. Above 750kg reversing lights are now also mandatory.

Connecting the supplied 13 pin Euro socket to an Australian 7-pin wired camper and adding the missing electric brake circuit was a joyous task given that IA didn't fit pins 10 thru 12. ISO11446 sets the 13 pin Euro wiring standard and colour codes and IA didn't follow it. I had to run a new circuit to create pin 12 to connect to pin 5 on my camper for the electric brakes.

Clark Kent said:

Connecting the supplied 13 pin Euro socket to an Australian 7-pin wired camper and adding the missing electric brake circuit was a joyous task given that IA didn't fit pins 10 thru 12. ISO11446 sets the 13 pin Euro wiring standard and colour codes and IA didn't follow it. I had to run a new circuit to create pin 12 to connect to pin 5 on my camper for the electric brakes.View attachment 7850866

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Yes, I don't understand why IA didn't follow ISO11446 nor drop the 3 pins either. There must because lot of caravan and camping trailer owners very p...ed off.
When I ordered mine I specifically asked their customer services was it a 13 pin socket, I should have asked was it an iso11446 European 13 pin socket.