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Hi all,

Our car is wired post 1998 but our caravan is wired pre 1998, can anyone tell me what is the best course of action to bring the two into line?

Quote: Originally posted by Tentz on 11/4/2010

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If you look here you will see difference pre & post. The wiring pattern is the same, I'd try it. as long as fridge works & battery charges while driving you will be ok. I towed an '88 caravan behind an '05 car & it worked ok.

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Here's another one to look at which seems quite clear.

http://www.a-tconsulting.co.uk/caravan_tech/12nschanges.html

Quote: Originally posted by Richie63 on 12/4/2010

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Thanks for your replies,
The fridge works fine but I am not sure if the battery is receiving a charge or not, how can I tell?.
Also, if it is connected through the permanent live would it not be draining the car battery whilst the ignition is off?

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Hi Ritchie, having a newer car and a pre 81 caravan I had similair problems and rewired the caravan to accept the new system for cars. 

I found this information helpful when sorting mine out.

Changes to 12s Wiring

The changes to the 12s wiring came into affect after the 1st of September 1998 so all 1999 models will have these changes incorporated.

• A feed to operate the caravan's reversing lights (if fitted) via Pin 1
• A 12-volt supply from the car battery via Pin 4 all the time your car is hitched up.
• A feed via Pin 6 to operate a fridge while the engine is running.
• A feed to charge the caravan's battery, which is only activated when the engine is running. This was previously via Pin 2 but charging will now operate via Pin 4.
• An earth connection. This was previously via Pin 3 alone but is now to be accompanied by another earth wire via Pin 7, exclusively for the fridge.

In recent caravan's, changes to the 12S wiring have necessitated altering the internal wiring system so that it:

• can draw a 12-volt supply from the tow car's battery via Pin 4 when the tow car engine is switched
  off.
• is able to take a 12-volt supply from Pin 4 and direct it exclusively and automatically to charge the
  caravan battery when the tow car engine is running
• ensures that when the engine is running, no internal 12v appliances can be operated other than the refrigerator.

Hopefully this will help sort your problem.
Incidentally I only noticed as the caravan battery lost power and did not charge when on route to cap site.
If not sure if the battery is being charged then check the voltage of the battery before setting off, if it is 12v or below and remains there it is not charging if when you arrive at destination it is above 13v then it is.

Thanks Tentz and Papa Pip,

I will have to check the voltage at the battery as you say.

Just thought I would let you know that I have checked the voltage at the caravan battery, and it is charging.

Thanks for all your help everyone