I'm going to upgrade my single towbar electrics to twin this weekend & I've bought the 12S wiring kit direct from Jaguar for my X-type. Reading the instructions there are no wires connected to pins 2 or 5 - ie they are not used. According to my research Pin 5 is a spare anyway so no big deal but Pin 2 should be switched live & its purpose is to charge the van battery. Why would Jaguar omit this feature from its kit? I'm assuming I cant take a feed from pin 6 which is the other switched live (fridge) as this would overload it?
Towbar wiring - 12s grey plug
- Thread starter Glenn_5132962
- Start date
Glenn
There are dozens of good diagrams on the net, have a trawl.
Two years ago I came across this suggestion. So far no more burn outs. If you choose to do it remember both car and caravan plug / socket must be modified.
"12s Pin Burn Out. Is There a Cure?
What Is The Problem?
Up to October 1997 and the introduction of new wiring standards for caravans and leisure vehicles, all the 12S system (with the exception of pin 1, yellow, reverse) relied on one heavy wire (pin 3, white) for the earth return. Pins 5 (brown) and 7 (black) were unused. Since EN1648-1, the central pin 7 (black) has been allocated as the refrigerator earth return and pin 2 (blue) is now redundant (previously battery charging circuit). These changes roughly coincide with the introduction of new larger fridge/freezers which, naturally, draw more current.
Pin 7 is an extended male segmented pin in the plug and acts as the 'lead' to guide the plug into the socket. As such, it is the one pin most likely to suffer damage in use. This, coupled with the higher current draw and the smaller cross sectional area of the wire is causing voltage drop, higher resistance, heat build up and consequently, melting plugs and/or sockets.
And The Answer?
You could change your double socket system on car and caravan to one of three continental 13 pin plug systems (either Jaeger or Feder/West Multicon). This, however, would entail changing other caravans and trailers that you may want to tow (though the Feder/West Multicon sockets will accept a standard 12N plug in the centre),and would prove expensive.
Alternatively, you could do a minor modification to the caravan 12S plug wiring. As pin 5 is unused, it is possible to link pin 7 to pin 5 and (provided the brown wire is earthed in the towing vehicle) share the load between both. Additionally, as pin 2 is now unused (though still probably connected to the split charge relay) the same can be done with the feed by linking pin 6 to pin 2.
The advantages are obvious. The combination of 2 cores gives a greater CSA than called for in the legislation and the load (feed and return) is shared by 4 pins instead of two. There will be less voltage drop, less resistance and less heat build up. It is a relatively simple DIY alteration and is inexpensive.
I would recommend using 28/0.30 (17.5 amp) cable for the linking wires.
Disclaimer
The information in this guide is as accurate as the writer is able to make it, however, no responsibility can be accepted for any inaccuracies which may be in the text. It is the responsibility of any person wishing to depend on the facts to check for themselves with original documentation or any updating regulations, instruments or changes in the law. Interpretation of the law is a matter for the courts.
Towbars & Trailers Davian Works, Storforth Lane Chesterfield S40 2TU Tel: 01246 202543 Fax: 01246 202543
There are dozens of good diagrams on the net, have a trawl.
Two years ago I came across this suggestion. So far no more burn outs. If you choose to do it remember both car and caravan plug / socket must be modified.
"12s Pin Burn Out. Is There a Cure?
What Is The Problem?
Up to October 1997 and the introduction of new wiring standards for caravans and leisure vehicles, all the 12S system (with the exception of pin 1, yellow, reverse) relied on one heavy wire (pin 3, white) for the earth return. Pins 5 (brown) and 7 (black) were unused. Since EN1648-1, the central pin 7 (black) has been allocated as the refrigerator earth return and pin 2 (blue) is now redundant (previously battery charging circuit). These changes roughly coincide with the introduction of new larger fridge/freezers which, naturally, draw more current.
Pin 7 is an extended male segmented pin in the plug and acts as the 'lead' to guide the plug into the socket. As such, it is the one pin most likely to suffer damage in use. This, coupled with the higher current draw and the smaller cross sectional area of the wire is causing voltage drop, higher resistance, heat build up and consequently, melting plugs and/or sockets.
And The Answer?
You could change your double socket system on car and caravan to one of three continental 13 pin plug systems (either Jaeger or Feder/West Multicon). This, however, would entail changing other caravans and trailers that you may want to tow (though the Feder/West Multicon sockets will accept a standard 12N plug in the centre),and would prove expensive.
Alternatively, you could do a minor modification to the caravan 12S plug wiring. As pin 5 is unused, it is possible to link pin 7 to pin 5 and (provided the brown wire is earthed in the towing vehicle) share the load between both. Additionally, as pin 2 is now unused (though still probably connected to the split charge relay) the same can be done with the feed by linking pin 6 to pin 2.
The advantages are obvious. The combination of 2 cores gives a greater CSA than called for in the legislation and the load (feed and return) is shared by 4 pins instead of two. There will be less voltage drop, less resistance and less heat build up. It is a relatively simple DIY alteration and is inexpensive.
I would recommend using 28/0.30 (17.5 amp) cable for the linking wires.
Disclaimer
The information in this guide is as accurate as the writer is able to make it, however, no responsibility can be accepted for any inaccuracies which may be in the text. It is the responsibility of any person wishing to depend on the facts to check for themselves with original documentation or any updating regulations, instruments or changes in the law. Interpretation of the law is a matter for the courts.
Towbars & Trailers Davian Works, Storforth Lane Chesterfield S40 2TU Tel: 01246 202543 Fax: 01246 202543
Hi,
Are you saying that post 1997, pin 2 is no longer used for charging the battery? In that case the wiring kit is correct then?
Are you saying that post 1997, pin 2 is no longer used for charging the battery? In that case the wiring kit is correct then?
Glenn
pin 1=reverse light
pin 2=sensing device
pin3=return earth for pin 4
pin4=interior lights etc or caravan battery charging (permanent supply)
pin5=not used
pin6=fridge(ignition controlled supply)
pin7=return earth for pin 6
pin 1=reverse light
pin 2=sensing device
pin3=return earth for pin 4
pin4=interior lights etc or caravan battery charging (permanent supply)
pin5=not used
pin6=fridge(ignition controlled supply)
pin7=return earth for pin 6
It depends on the age of the caravan. The car should be wired to be compatable with the caravan. If the van is pre 97 then the battery charge is on pin 2 [ switched on by a relay in the car which senses the engine is running]. Post 97 it is unswitched on pin 4.
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