On 24/05/2017 20:57, Harry Bloomfield wrote:
Michael Chare formulated the question :
I presume cars are made a economically as possible, so is it really
the case that a rear light unit with LEDs and driven by CAN bus, with
two thin wires for the power and two even thinner wires for CAN-H and
CAN-L bus is really cheaper to make than one with convention bulbs and
much thicker wires?

The modern system does not make connecting a trailer light socket easy!

Actually, it makes it easier and it can be more clever. One thick wire
as the main supply, then thin wires can be used to pick up the signals.
The trailer lights can be monitored and issues fed as data down the
can-bus.

Yes. And then you plug in a trailer with LED lights and the damned
monitoring pulse causes the lights to visibly flash every few seconds. I
had to change the trailer back to filament lamps thus losing the
reliability benefit - grrrr!

SteveW