ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades 12N/12S Vehicle & Trailer wiring

Paul,

Here is a picture of the pin layout (and wiring colour coding) of the plug (male):



Pin designations are as follows:

• 1 - Left Hand Turn (Yellow)
• 2 - Reverse (Black)
• 3 - Earth (White)
• 4 - Right Hand Turn (Green)
• 5 - Service Brakes (Blue)
• 6 - Brake Lights (Red)
• 7 - Tail Lights (Brown)

[This message has been edited by Trumpy (edited 08-01-2006).]

Hmm... The pin numbering on your flat connector seems to correspond closely to that of the 12N standard here, with reverse in place of fog light and an electric brake line in place of one of the tail-light feeds.

Do the same pin numbers apply to the New Zealand 12N-style round connector?


Funnily enough, I think it was on a Skoda that my mother had when I was a kid which first brought the arrangement to my attention. (Signal, stop at the curb, signal switch doesn't cancel, switch off, get out, and then wonder why half the parking/tail lights are on.)


Just in case any of our European readers are not aware of the differences, let's explain that it is still normal in North America for vehicles to use combined red turn/brake lights.

I'm not sure about other countries, but here in the U.K. all new vehicles built for the British market have had separate amber turn signals on the rear since the mid 1960s, hence the separate left turn/right turn/brake connections on the 12N connector.

In the U.S. & Canada you can buy a converter unit so that a car with independent amber signals can be connected to a trailer (which will have the standard combined red brake/turn lights).


I know that the 7-pin Bargman-style connector is becoming pretty much the standard over there now, but how common are the 5- and 6-way round connectors?
http://www.horsetrailerworld.com/home/wiring.asp

Any idea when these various formats were introduced?

By the way, it seems from Mike's post that New Zealand also has electric trailer brakes, but you won't find them here on regular utility trailers and caravans (travel/camping trailers). Inertia/surge brakes with a direct mechanical linkage from the towing hitch to the brakes is the norm here (except for the smallest trailers with no brakes).



[This message has been edited by pauluk (edited 08-01-2006).]

I don't know, athough the Bargman type connector is mostly used on the fifth-wheel and goosneck type trailers, and the 4 pins or 6 pin round (which a couple of our trucks have installed), with ball hitch trailers.

Fifth-wheel trailers are quite rare over here. Almost all utility and camping trailers these days use a 2-inch ball hitch.

The turn signal switch turning on one side of the "parking lights" with the ignition off was for parking in an unlit area. Think it was a German requirement in the 60's/70's. It may have also lit a small bulb in the headlight on the selected side.

Ah, that sounds quite plausible. I suppose that also ties in with the specification for the 12N connector which says that the right-hand tail circuit should also feed the license plate light. That way when parking on the right at night, one could leave the left-hand lights on without the plate light adding to the current drain.

The arrangement would be completely useless in Britain. If parking in a place which requires lights, we need to leave all the parking/tail lights on, not half of them!


On many European cars a small bulb set in the side of the headlamp reflector is the front parking light.

British cars have used several configurations of front lights in the past:

1. Combined parking light & turn signal with dual-filament bulb (equiv. to #1157) behind a white lens, just like the standard pre-1963 American arrangement (although on some vehicles the parking lights remained on when the headlights were switched on, as with all post-1968 U.S. vehicles).

2. Separate white parking lights and amber turn signals, each with its own bulb (either in two entirely separate assemblies or a double cluster but still effectively separate).

3. Parking light incorporated into the headlight, and a separate amber turn signal.

Configuration #1 went out of use from 1965 when cars had to be fitted with amber signals but were still required to have white parking lights (thus ruling out modern U.S.-style combined amber park/turn lights for U.K. market cars).

While there are still some cars using method #2, they're becoming less usual, and method #3 is pretty much the norm on most new vehicles now.

While we're on the subject, a few other U.S. vs. U.K. vehicle lighting differences amber/red side marker lights and reflectors are not required on regular cars here and are not normally fitted. Larger trucks, buses etc. are required to have clearance lights on the upper corners, but don't have to be fitted with the three width ID lights in the center.

Also, in British parlance, you might hear the term "side lights." That doesn't refer to side marker lights, but is actually the more usual colloquial name here for the front parking lights. (In government-speak they're called "front position lamps.")

All in all, the different configuration means that those of us who drive U.S. vehicles here tend to "stand out from the crowd" a little with our different lights.