It happens that NY formulated :
I've seen some cars with two 7-pin connectors and I presumed that the second
was for the things like permanently and switched live and reversing lights.
What is odd is that my parents had our caravan (Lynton Javelin - how do I
still remember that name) in the early 70s, I'm *sure* we only had one 7-pin
socket and not a second one. OK, I was about 10 at the time, but I was at an
age when anything "different" stuck in my mind. Maybe I've mis-remembered.

I'm not sure when the 12S use began, but I don't think it was around in
1970. Caravans back then were much more basic - no fridge, no batteries
gas lighting. Maybe mid 1990's they became more common as they were
fitted with more luxuries. 12N - N stands for Normal, 12S the S is
Supplementary.


The 15pin replaces both 12N and 12S with a single socket and plug, which is
supposedly more robust.

Do you mean 15- or 13-pin? Is there another third type of connector?

Sorry, I mistyped it is of course a 13 pin.