Continental caravan wiring help needed

[Paulypaul]

We've owned a 1975 Constructam Coral caravan for a few years now and are just getting it ready to sell this year. I've had issues with the lighting so decided to renew the rear light clusters.

However, I've run into trouble: it does have 7 core wiring but the wires that go to the actual lights have me stumped?

7 core wire goes from the plug into the under bed locker at the rear of the van. From there the white, yellow, brown and green wires go out to the rear of the van. The black, red and one of the brown wires go somewhere else?

At the light clusters the wiring is as follows:

Right hand side - 1 x white, 2 x yellow, 2 x brown.
Left hand side - 1 x yellow, 1 x brown, 1 x green

I changed the 7 pin plug that goes into the tow vehicle and when it is plugged into my car they no longer work as they should and they seem to work randomly?

If anyone can offer any help I qould be very grateful.

Thanks, Paul

 

[Spriddler]

I believe the wiring is fairly standardised.
This any help?

 

[pappajohn]

Using the above diagram..... 2, 3, 5, 6 and 7 may be piggy backed from one cluster to the opposite one. 1 and 4 being left and right handed.
No point in a seperate wire from the socket or joint box to feed each individual stop, tail, fog and earth

 

[Paulypaul]

Yeah I did wire the plug as per the diagram but it would appear that the wires going to the individual lights don't correspond i.e yellow brown and green wires go to the left hand light?

 

[Spriddler]

Well if the wiring is a b*gger's muddle you'll just have to identify the feeds by a process of connecting one at a time and see which lamp lights, or trace each wire at each end with a meter.
I can't see why they would work 'randomly' unless there's a faulty earth somewhere when lights can behave illogically as the current seeks an alternative earth return path to that provided for/at the lamp units.

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[mitzimad]

that diagram is missing a vital bit of infomation which way your reading the number from front of back of the plug/socket

 

[mitzimad]

https://www.caravanclub.co.uk/media/1022790/towbar-wiring-mo.pdf
this one is more accurate about what your looking at

 

[pappajohn]

that diagram is missing a vital bit of infomation which way your reading the number from front of back of the plug/socket

Yep.... That looking at the front face, not the wiring terminal side

 

[Spriddler]

On the one that I fitted to my son's caravan last year the number of each pin was moulded into the plug.

 

[Lenny HB]

Should be easy enough to buss the wiring through. Take the bulbs out first and buss through with a meter obviously you will have to extend one of the meter leads.

I'm surprised it has a 7 pin plug I thought they went out with the ark.

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[pappajohn]

My trailer, new two years ago from Poland, has a 7 pin.
It's even mentioned on the cert of conformity.

 

[Spriddler]

My trailer, new two years ago from Poland, has a 7 pin.
It's even mentioned on the cert of conformity.

Yebbut, it won't need feeds to a fridge, reversing light, or to charge the battery. (Mind you, the OP's doesn't have those either unless there are two sets of plugs/sockets as there were on my son's car).

 

[pappajohn]

Yebbut, it won't need feeds to a fridge, reversing light, or to charge the battery. (Mind you, the OP's doesn't have those either unless there are two sets of plugs/sockets as there were on my son's car).

Caravans will either have a 13pin or 2 x 7pin to cover all that stuff.
One 7 pin for compulsory road lighting
One 7 pin for hab stuff.

 

[Spriddler]

Caravans will either have a 13pin or 2 x 7pin to cover all that stuff.
One 7 pin for compulsory road lighting
One 7 pin for hab stuff.

Indeed so, quite correct. We used an adapter to convert the two 7 pin car sockets to one 13 pin socket to match the 13 pin caravan plug.

 

[autorouter]

At the light clusters the wiring is as follows:

Right hand side - 1 x white, 2 x yellow, 2 x brown.
Left hand side - 1 x yellow, 1 x brown, 1 x green

My guess is, the colours are nothing like that standard diagram. The only way these colours make sense is,
white = Right indicator
green = left indicator
brown = tail lights
yellow = brake lights
maybe the brown and yellow are the opposite.
There are not enough wires for there to be an earth wire, so maybe the earth is wired to the caravan chassis. was there another wire near the rear clusters that went to the chassis?
Do the red and black wires go to a caravan battery or fridge? The black might be the earth wire, connected to the chassis near the battery/fridge.

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[Paulypaul]

My guess is, the colours are nothing like that standard diagram. The only way these colours make sense is,
white = Right indicator
green = left indicator
brown = tail lights
yellow = brake lights
maybe the brown and yellow are the opposite.
There are not enough wires for there to be an earth wire, so maybe the earth is wired to the caravan chassis. was there another wire near the rear clusters that went to the chassis?
Do the red and black wires go to a caravan battery or fridge? The black might be the earth wire, connected to the chassis near the battery/fridge.

I'll check this out! The black and red and one of the brown wires seem to be routed elsewhere once they come inside the caravan as per the picture. Thank you.

 

[Lenny HB]

My trailer, new two years ago from Poland, has a 7 pin.
It's even mentioned on the cert of conformity.

Trailers often come with 7 pin but most caravans changed to 13 pin over 25 years ago. Last time I fitted a towbar in 2012 it came with a 13 pin socket.

 

[Paulypaul]

This is a 1975 Constructam made in Belgium. We are only the third owners and have owned it for 5 years. I went to Holland to buy it and just wondered if the foreign wiring of that era was different to the 7 core wiring im used to over here? Glad there isn't 13 wires though

 

[autorouter]

I'll check this out! The black and red and one of the brown wires seem to be routed elsewhere once they come inside the caravan as per the picture. Thank you.

If the brown wire is for the tail lights, maybe the extra brown wire is for the marker lights (if there are any).

 

[Paulypaul]

Ahh yes there are marker lights. I didntbget a chance today but I'm going to try and sort it tomorrow.
Thanks very much for your help.

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[pappajohn]

Trailers often come with 7 pin but most caravans changed to 13 pin over 25 years ago. Last time I fitted a towbar in 2012 it came with a 13 pin socket.

The one I fitted 3 years ago to my Hyundai came with a 7 pin and the one seven years ago to my Chrysler 300C was also 7 pin.
Both had a 7 way CanBus relay module.
The two or three caravans I've had in the last 10 years all came with a 7 pin... Even the Hobby.
13 pin are a lot more recent as a standard fit than you think.

 

[Lenny HB]

The one I fitted 3 years ago to my Hyundai came with a 7 pin and the one seven years ago to my Chrysler 300C was also 7 pin.
Both had a 7 way CanBus relay module.
The two or three caravans I've had in the last 10 years all came with a 7 pin... Even the Hobby.
13 pin are a lot more recent as a standard fit than you think.

I bought a new Hobby caravan in 2002 it had a 13 pin plug, I bought it in Germany.
13 pins were coming into use when I worked in the industry and that was 30 years ago and were standard on German caravans, often changed on imported vans.

 

[Ian Bosman]

We've owned a 1975 Constructam Coral caravan for a few years now and are just getting it ready to sell this year. I've had issues with the lighting so decided to renew the rear light clusters.

However, I've run into trouble: it does have 7 core wiring but the wires that go to the actual lights have me stumped?

7 core wire goes from the plug into the under bed locker at the rear of the van. From there the white, yellow, brown and green wires go out to the rear of the van. The black, red and one of the brown wires go somewhere else?

At the light clusters the wiring is as follows:

Right hand side - 1 x white, 2 x yellow, 2 x brown.
Left hand side - 1 x yellow, 1 x brown, 1 x green

I changed the 7 pin plug that goes into the tow vehicle and when it is plugged into my car they no longer work as they should and they seem to work randomly?

If anyone can offer any help I qould be very grateful.

Thanks, Paul

The colour coded cable should comply with the standard for a !2N plug/socket so that you need to look up the code - bracketed numbers are the PIN numbers. The brown (5) goes to the right hand rear lights, black (7) to the left hand rear lights with white (3) as earth. Red (6) goes to the brake lights. Yellow (1) is left indicator and green (4) right indicator. Blue (2) is for the fog light if there is one on your van but suspect that the year of the van is too old for that so ignore it unless it was wired for the fridge or the van battery. Any other services such as battery charging, fridge should be on another 12 pin plug, 12S, the pins are similar layout but a couple are reversed from a plug to a socket, etc so cannot be inserted wrongly. Modern vans BTW now have 13 pins combining the functions of both 12N/S and are much more reliable and less likely to detach in service. Check that the wires in the caravan plug conform the colours and check that they continue through the van, often the whole set are near the front and then subsidiary cable go off to the lights with colours not always conformant. A good meter will help trace the necessary

 

[Paulypaul]

The colour coded cable should comply with the standard for a !2N plug/socket so that you need to look up the code - bracketed numbers are the PIN numbers. The brown (5) goes to the right hand rear lights, black (7) to the left hand rear lights with white (3) as earth. Red (6) goes to the brake lights. Yellow (1) is left indicator and green (4) right indicator. Blue (2) is for the fog light if there is one on your van but suspect that the year of the van is too old for that so ignore it unless it was wired for the fridge or the van battery. Any other services such as battery charging, fridge should be on another 12 pin plug, 12S, the pins are similar layout but a couple are reversed from a plug to a socket, etc so cannot be inserted wrongly. Modern vans BTW now have 13 pins combining the functions of both 12N/S and are much more reliable and less likely to detach in service. Check that the wires in the caravan plug conform the colours and check that they continue through the van, often the whole set are near the front and then subsidiary cable go off to the lights with colours not always conformant. A good meter will help trace the necessary

Thank you

 

[Paulypaul]

My guess is, the colours are nothing like that standard diagram. The only way these colours make sense is,
white = Right indicator
green = left indicator
brown = tail lights
yellow = brake lights
maybe the brown and yellow are the opposite.
There are not enough wires for there to be an earth wire, so maybe the earth is wired to the caravan chassis. was there another wire near the rear clusters that went to the chassis?
Do the red and black wires go to a caravan battery or fridge? The black might be the earth wire, connected to the chassis near the battery/fridge.

I had another go today and I'm completely stumped now? I tried to wire the plug that goes into the car to correspond with what can only be assumed are active wires as per above. Side lights both worked OK but when the brakes were pressed the indicators illuminated very dim?

I also found a black and a red wire near the fridge, although the red was terminated and the black just laying there.

The front marker lights did not work with the rear lights and I discovered that the nearside front marker had 2 x red wires and 2 x brown wires (the brown wire connecting to the bulb holder) The offside marker light was the same only single wires?

Some weird stuff going on here?

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[autorouter]

I had another go today and I'm completely stumped now? I tried to wire the plug that goes into the car to correspond with what can only be assumed are active wires as per above. Side lights both worked OK but when the brakes were pressed the indicators illuminated very dim?

Can't be sure, but this sort of thing is usually a sign that the earth return ie the negative wiring has a problem.

Some of the old light clusters had a negative return through the mounting bolts to the chassis frame, rather than s proper wire. Maybe you could check, if you still have the old light clusters To fit a new light cluster, you may have to run a wire locally from the negative cluster terminal to the chassis frame. That's assuming it's a bit too much work to wire in a full negative earth return wire.

I also found a black and a red wire near the fridge, although the red was terminated and the black just laying there.

Is/was the red wire connected to the fridge? If not, is there space for a battery where the red and black wires end?

I changed the 7 pin plug that goes into the tow vehicle and when it is plugged into my car they no longer work as they should and they seem to work randomly?

When you changed the plug, did you wire it exactly as it was before, or did you change it to be like a standard 7-pin wiring diagram? Did the wiring work in the past, when plugged into a standard vehicle 7-pin socket?

 

[Ian Bosman]

I had another go today and I'm completely stumped now? I tried to wire the plug that goes into the car to correspond with what can only be assumed are active wires as per above. Side lights both worked OK but when the brakes were pressed the indicators illuminated very dim?

I also found a black and a red wire near the fridge, although the red was terminated and the black just laying there.

The front marker lights did not work with the rear lights and I discovered that the nearside front marker had 2 x red wires and 2 x brown wires (the brown wire connecting to the bulb holder) The offside marker light was the same only single wires?

Some weird stuff going on here?

Sounds like someone has been “buggering about” with the wiring. Get a good multimeter and test everything from the plug end of the caravan to a point where you can access the Des of the cable coming from it. Note which pin has which colour plus what colour goes from it. There MUST be an earth on the white cable which is probably the source of all your problems if you say that there is no earth

I had another go today and I'm completely stumped now? I tried to wire the plug that goes into the car to correspond with what can only be assumed are active wires as per above. Side lights both worked OK but when the brakes were pressed the indicators illuminated very dim?

I also found a black and a red wire near the fridge, although the red was terminated and the black just laying there.

The front marker lights did not work with the rear lights and I discovered that the nearside front marker had 2 x red wires and 2 x brown wires (the brown wire connecting to the bulb holder) The offside marker light was the same only single wires?

Some weird stuff going on here?

None of what autoroute says makes sense as those are not the proper colours. The CAMC and C&C have all the stuff. I would suggest that you take apart the 12N plug, identify what colours are on the pins and follow it from there. I had a Burstner as my last caravan and they were all correctly coded down to the lights at the back and front. but you have a very old caravan and maybe a previous owner get them all muddled. The white earth, as I say, is crucial as the caravan chassis should never be the earth. The earth is taken from the towing vehicle as that is the source of the power. I might be a better option to rewire the whole thing using a standard 7 core cable and distributing off from there by getting a mutiny connector as it enters the van body correctly wired and then branching off. Each light cluster will need the +ve to the centre pin of the bulb and the white earth to the outer
-ve. You will find that the side markers are duplicating the rear side markers, one cable acts as supply for the brakes at the rear with the two side brake likes linked together. If you do have a cluster with all the lights in one housing there will be only one earth connection going directly back to the white pin on the cars socket via the plug. Indicators use one _+ve for left and one +ve for right again a white earth on each. Note that if the lights are all separate then you will have to have an earth on each. Make sure that the earth connections are all clean and not earthed to the caravan chassis.

 

[Ian Bosman]

Can't be sure, but this sort of thing is usually a sign that the earth return ie the negative wiring has a problem.

Some of the old light clusters had a negative return through the mounting bolts to the chassis frame, rather than s proper wire. Maybe you could check, if you still have the old light clusters To fit a new light cluster, you may have to run a wire locally from the negative cluster terminal to the chassis frame. That's assuming it's a bit too much work to wire in a full negative earth return wire.

Is/was the red wire connected to the fridge? If not, is there space for a battery where the red and black wires end?

When you changed the plug, did you wire it exactly as it was before, or did you change it to be like a standard 7-pin wiring diagram? Did the wiring work in the past, when plugged into a standard vehicle 7-pin socket?

Te fridge on old van often was wired in through he 12N but they were never intended to be, you need a 12S plug and socket or better a 13 pin plug and socket which is what I would do if wiring from scratch. BTW, I have a Sealey towing plug tester, the socket on the car is part of the MOT.

 

[Paulypaul]

I do have the old light clusters somewhere and I think it had a short length of wire in there which I thought looked a bit of a bodge...obviously not.

I have to admit I never took any notice of how the old plug was wired as I assumed it was just standard wiring cause it all worked when hooked up to my car?

Thank you for your advice, I'll dig out the old clusters and try your suggestions with the earthing. The red and black wires under the galley are standard guage but I'm not sure if they are in the location of where a battery would be but I'll look for some tell tale signs.

Once again, thanks for your advice.

Paul

 

[autorouter]

Te fridge on old van often was wired in through he 12N but they were never intended to be, you need a 12S plug and socket or better a 13 pin plug and socket which is what I would do if wiring from scratch. BTW, I have a Sealey towing plug tester, the socket on the car is part of the MOT.

Before rear fog lights, you could just about get away with that. I wonder if the original clusters had fog lights? I suspect not.

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