On 24/05/2017 20:50, Michael Chare wrote:
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!



There's also the subtle point that one thick cable (my car also has a
fusebox in the boot) and plug in modules can cope with all the possible
factory options without having unneeded wires in the loom, or even worse
a custom loom.

Plus the ability for the BCM to substitute a failed lamp for an
alternative is quite useful. If sometimes confusing

And I'd argue that as long as you are using the right parts, it makes
wiring a trailer socket many times easier...though it obviously costs
more than using generic adapters