Twin electrics

[twindaddy]

Hi all
new twin electrics fitted on tow vehicle today. My caravan is 1996, and I think the grey socket has been wired to post 1998 caravan style. Pin 4 is permanent live, which on my van I think this should have been pin 2. I only know/ask this as I have a back up cable made to use if leisure battery runs low, I connect the cable to the grey socket on vehicle and grey socket on van and I can use the cars battery to run the 12v I. Emergency (overnight etc). The said emergency cable is wired as pin 2 live and pin 3 earth!!

What you say??

thanks
TD

 

[twindaddy]

Hi all
new twin electrics fitted on tow vehicle today. My caravan is 1996, and I think the grey socket has been wired to post 1998 caravan style. Pin 4 is permanent live, which on my van I think this should have been pin 2. I only know/ask this as I have a back up cable made to use if leisure battery runs low, I connect the cable to the grey socket on vehicle and grey socket on van and I can use the cars battery to run the 12v I. Emergency (overnight etc). The said emergency cable is wired as pin 2 live and pin 3 earth!!

What you say??

thanks
TD

forgot to add, how will this work when towing?

 

[TD42]

yes you are correct the auxillery grey plug wiring was changed in 1998 so you need to wire your 12 s to the pre 98 designation

 

[twindaddy]

Thanks, is it just a simple case of taking the socket apart and swapping wires on pins 2 and 4?

 

[colin-yorkshire1]

Thanks, is it just a simple case of taking the socket apart and swapping wires on pins 2 and 4?

hi TD, if was me I swop the wires in the van plug an the extension, and leave the tow socket alone, the main reason is if its wired post 98, it will be corrrect for any later van, you wish to tow,
one other point I dont know how the fitter has wired the charge wire, it could be that there is no perminant feed (once the engine is turned off,

 

[twindaddy]

Thanks Colin.

The extension cable I use for Emergency 12v I have sorted, I will just put live to 4 and earth to 3 (Pre 98 was 2&3). Am I right in thinking that when towing, as my van is '96 and the tow elecs are now '99, the fridge won't power and the battery won;t charge? Can I re-wire anything so it does?

Cheers all

 

[colin-yorkshire1]

hi TD,
of course you can!!. but for my money "so to speak" I would do the van end rather than modify the new installation on the car, it really depends on wether there is a perminant feed down the wire from pin 4, without the engine running, you will have to check this,
pin 2 on the new configuration is just a sensing wire (ATC ect) pin 6 is the fridge in both configurations so should not be affected.
on my older vans pre m/home, I too used a fly lead from the car to the van to get 12v power to the van, when the battery was low (before EHU's) but the new bailley (2005) does not have a habitation relay, and takes all the 12v power from the van battery this is then topped up by either the use of the cars charge circuit or EHU, a fly lead will not work as there is no connection from car to van on a perminant feed.
if you do have live feed down pin 4 it should be a simple case of changing the wires on the flylead and van plug to pin 4, then everything should work as before, however if there is no live feed (engine off ) from pin 4 the problem gets a litte more pragmatic and difficult to solve, it can be done but involves using spare wires and rewiring to seperate interior lighting from the charge circuit,
but I will not go there just yet, in case a simpler solution works.

 

[twindaddy]

Colin
Thanks, I was thinking that was the case and now you have confirmed, I will go ahead and change the wire to pin 2 to pin 4 on both my fly lead and the caravan plug. Power is live on pin 4 which is how I knew things were not as I wanted them.

I'm away for 3 weeks with no EHU so really wanted the fly lead, so feel much better now.

Cheers
TD

 

[Gafferbill]

Hi......you need to be careful here as it would appear from your post that the fitter has assumed that your caravan is fitted with a 12 volt relay whereas in fact that may not be the case.

See here.........Differences in plug (not socket) wiring

You will have to choose one or other of the wiring systems .....it will not be successful to mix and match IMO.
If using the later system you will probably have to fit a battery charging relay to your caravan controlled by a sensing wire from the car via pin 2.

 

[colin-yorkshire1]

hi TD,
glad there seems to be an easy solution, let us know how it works,
GafferBill is right of course you have to be carefull mixing old and new configuratons, one of the alternatives is to use a smart relay(normally used on the car side), wired into the van electrics, with a perminant feed on pin 4 straight from the car battery "with a 20amp fuse" to split the power, at the van end,
the fly lead would then still work as it would carry this power from pin 4 straight to the van,

 

[twindaddy]

All works. Caravan socket still wired as was (Pre '98) and the plug on the extension lead wired to post '98 to match the tow vehicle.

Fridge works when towing (don't know about battery being charged as it was full before leaving on trip)
Also, extension fly lead works to allow caravan to use the car battery as a leisure battery as tried it last night.

Perfect for me, thanks all
TD