In article , Andy Burns
writes
Michael Chare wrote:

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?

Well yes, because thick copper is expensive, and those 4 wires (and
multiple CAN chips) can individually drive
tail/brake/indicator/reverse/fog lamps ...

Also the chips start to do snazzy things such as dimming one side's
front running lamps when indicating or providing the "moving pulse" on
newer indicators
And switch off vehicle rear fog but leave on trailer fog.
--
bert