Daniel J. Stern wrote:
> C. E. White wrote:
>
>> For some reason, in some vehicles, the power feed to the switch
>> is live all the time. I have no idea why they use a live feed
>> in some vehicles.
>
> Because for those specific vehicles, it allowed them to save
> $0.01 per vehicle in wire not used. That is how Ford (among other
> companies) make decisions. Pennies make promotions.

If the problem is degradation of the barrier between the wire
and the brake fluid, then having it live all the time would
make no difference as to whether or not the vehicle is going to
catch on fire at some point.

Having it only live when the key is on means that the car would catch
on fire while people are in it, rather than while it's empty.
(More danger to human life?)