Converting pre-1998 caravans to the euro plug
A few who have converted their older caravans to the euro plug with the aid of my instruction leaflet think it would be beneficial for others if I was to post the basic modification instructions on club together. Should you prefer the full in detail instructions,
please email me.
WARNING; These instructions are for converting caravans built before September 1998 to the 13 pin euro plug. If your caravan was sold as new within a year from this date, it maybe old stock from the previous year, if you are unsure of the exact age of your
caravan then you must email me for the full instruction leaflet, this will explain how to identify previously & post September 1998 wired caravans.
Converting caravans built before September 1998 to the euro plug require a simple modification in order to make them compatible to be upgraded to the euro plug system, this is due to them requiring three positive power supplies (2 x ignition & 1 x permanent)
and one earth return wire for the caravans auxiliary functions. All post September 1998 built caravans (weather 12n/12s or euro plug as standard) require two positive power supplies (1 x ignition & 1 x permanent) and two earth return wires for the caravan
auxiliary functions. We must firstly modify the said caravan to the post September 1998 said wiring specifications in order to upgrade the caravan to the euro plug system. Secondly, after this has been done, we then convert the caravan to the euro plug using
the normal methods described by many other caravan club members, this is more or less a simple change to 13 core euro cable and a pin for pin swap and rewire of the plugs. Some of the said older caravans which are in need of the modification have habitation
relays factory fitted but many do not, you must follow the instructions below regardless of weather your caravan has the relay or not.
Lets get started;
At this present time your caravan should be wired to the prior September 1998 wiring system with no modifications, otherwise things may clash if the wiring has been modified in any way.
You will need to obtain a 12 volt, 30/40 Amp, 4 pin standard vehicle relay the connection numbers should be; 85/86/87 & 30.
Find the location within your caravan were the two electrical supply cables (12n/12s) entire the inside of your caravan, this should be somewhere near the front of the caravan possibly under the seating area, at the point where the two cables entire should
be a junction box or possibly just a bunch of wires and connection blocks acting as a junction box.
WARNING; Do not get muddled up between the two cables the outer sheath of the 12n cable is black and the 12s cable is light grey (could also be white) as both cables have the same colour cables within them but the light grey 12s cable has heavier gauge wires
within it due to its functions. Disregard the black 12n cable as we are only concerned with the wires within the light grey 12s cable for this modification.
WARNING; Make sure the caravan's leisure battery, mains electrical power and drawing vehicle are disconnected from the caravan before starting work.
Firstly, locate the blue wire within the light grey 12s cable at the said junction point, cut the blue wire as close to the light grey outer sheath as you can so as not to bypass any in line fuse which may be present making sure you have enough length of
wire to work with.
Having cut the blue wire, you now have two ends of said wire, disregard the end that enters into the light grey outer sheath and connects to the drawing vehicle via the 12s plug, connect the other end of the cut cable to terminal 30 on the new relay.
Secondly, locate the green wire within the light grey 12s cable at this same junction point, connect/join terminal 87 of the relay to this green wire as close to the light grey outer sheath as you can making sure the wire is still connected within its self.
Thirdly, locate the red wire within the light grey 12s cable at this same junction point, connect/join terminal 85 of the relay to this red wire as close to the light grey outer sheath as you can making sure the wire is still connected within its self.
Fourthly, locate the thick white earth return wire within the light grey 12s cable at this same junction point, connect/join terminal 86 of the relay to this thick white wire as close to the light grey outer sheath as you can making sure the wire is still
connected within its self.
Finally, as mentioned previously there are two earth return wires for the auxiliary supplies on post September 1998 wired caravans, this second earth return wire is a separate earth return for the caravan's fridge, this must also be addressed for compatibility
within the required modification.
This may not be quite so easy as it maybe difficult to find the wire in question. You will need to locate the fridge's internal earth return wire within the caravan and connect it directly to pin 7 within the caravan's 12s plug, I can give you a clue as
to where you should find it, it should be connected directly or indirectly to the thick white earth return wire you tapped into when you connected terminal 86 of said relay. Unfortunately, you are on your own in locating this wire as only you are able to examine
your own caravan.
When you have located the fridge's internal earth return wire, you will need to disconnect it from its present connection and reconnect it to the disused black wire found within the light grey 12s cables sheath inside the caravan at the same junction point
where you located all of the other wires, you may have to cut back some of the light grey outer sheath in order to expose it as it is not used or connected on these older caravans.
In addition to this, you will also need to connect this new black fridge earth return wire to pin 7 at the 12s plug end of the cable. If you are unable to locate this disused hidden black wire within the light grey 12s supply cable then improvise and connect
the new fridge earth return wire to the other end of the blue wire you disregarded earlier, remembering that this blue wire must be disconnected from pin 2 and reconnected to pin 7 at the 12s plug end of the cable. If you are improvising with this blue wire,
to be professional, you would need to tag/label both ends of the wire with a black sheath/sleeve for future identification.
The modification in question is now completed and the caravan is converted to the post September 1998 wiring changes, it now has 2 x positive power supplies (1 x ignition & 1 x permanent) and two earth return wires for powering the caravan auxiliaries, it
is now compatible to be upgraded to the 13 pin euro plug system.
Upgrading to the new 13 pin euro plug system at this stage is more or less a change to 13 core supply cable and a pin for pin swap and rewire of the plugs. Colour codes and pin allocations for the euro plug are available from the caravan club or my full
instruction leaflet, there are three different colour code schemes used for the euro plug, one appears to be the most common within the UK.
CONCLUSION; When you decide to upgrade to the 13 pin euro plug, you have a choice, you can either fit the euro plug directly to your 12n/12s existing cables or carry out the full professional conversion by replacing the two 12n/12s supply cables with the
single 13 core euro cable and plug. Euro plugs are available with 12n/12s dual inlets to fit the old twin cables as well as being available to fit the new 13 core euro cable directly. My public email should you require full instructions, micro-soft word doc;
colin-handcock@hotmail.co.uk,
Regards
Snowy