"Andy Burns" wrote in message
...
bert wrote:

Andy Burns wrote:

the chips start to do snazzy things such as

switch off vehicle rear fog but leave on trailer fog.

I thought the 7 pin sockets had been doing that with an inbuilt switch for
decades?

The 7-pin (as opposed to 13-pin) socket doesn't have a pin that is dedicated
for use by foglights? They have separate pins for left- and right-hand tail
lights (why?) but none for fog lights - unless you sacrifice the permanent
12V feed for a fridge. When my parents had a caravan in the early 70s, they
had an extra wire for foglights which they had to remember to plug/unplug
when they were hitching/unhitching the caravan. While some cars may have
once had side/tail lights that could be controlled individually, for use as
parking lights, it seems weird to waste a pin replicating that onto the
trailer, when it means you can't have both permanent live and fog lights.
Mind you, the lack of a reversing light pin is also odd: how else is the car
behind supposed to know that you intend to reverse?