>The short answer is that in this case the resistance of the
switch went >from essentially zero to some larger value, but the
circuit still has >anohter element, the brake lights. Therefore
the current way have been >reduced somewhat by the increase in
reistance in the switch, but the switch >now is carry a somewhat
reduced current, but at a greater currect so it ws >heating up,
as power = I*I*R. >69 MGC-GT coming together. Let's try this
again. Purely theoretical: If the brake circuit consisted only
of the switch and brake lights (and a 12 volt battery), and the
brakes normally drop 12 volts, and the switch zero, than the
brake lights are dropping all the voltage and therefore
dissipating all of the heat. If the switch takes on resistance,
let's say equal to that of the brake lights combined, each part,
the brake lights and the switch, will drop 6 volts, assuming
they are in series. It is this voltage drop, dissipating power,
which creates heat (or motion in a motor, or whatnot, but in the
switch, it had not